diff --git a/backends.py b/backends.py
index e98cef474..86cf6aab2 100644
--- a/backends.py
+++ b/backends.py
@@ -68,7 +68,7 @@ class Backend():
         return filename
 
     def get_target_dir(self, target):
-        if self.environment.coredata.layout == 'mirror':
+        if self.environment.coredata.get_builtin_option('layout') == 'mirror':
             dirname = target.get_subdir()
         else:
             dirname = 'meson-out'
@@ -208,16 +208,16 @@ class Backend():
     def generate_basic_compiler_args(self, target, compiler):
         commands = []
         commands += compiler.get_always_args()
-        if self.environment.coredata.buildtype != 'plain':
-            commands += compiler.get_warn_args(self.environment.coredata.warning_level)
+        if self.environment.coredata.get_builtin_option('buildtype') != 'plain':
+            commands += compiler.get_warn_args(self.environment.coredata.get_builtin_option('warning_level'))
         commands += compiler.get_option_compile_args(self.environment.coredata.compiler_options)
         commands += self.build.get_global_args(compiler)
         commands += self.environment.coredata.external_args[compiler.get_language()]
         commands += target.get_extra_args(compiler.get_language())
-        commands += compiler.get_buildtype_args(self.environment.coredata.buildtype)
-        if self.environment.coredata.coverage:
+        commands += compiler.get_buildtype_args(self.environment.coredata.get_builtin_option('buildtype'))
+        if self.environment.coredata.get_builtin_option('coverage'):
             commands += compiler.get_coverage_args()
-        if self.environment.coredata.werror:
+        if self.environment.coredata.get_builtin_option('werror'):
             commands += compiler.get_werror_args()
         if isinstance(target, build.SharedLibrary):
             commands += compiler.get_pic_args()
@@ -302,9 +302,10 @@ class Backend():
             outdir = self.environment.scratch_dir
             fname = os.path.join(outdir, p.filebase + '.pc')
             ofile = open(fname, 'w')
-            ofile.write('prefix=%s\n' % self.environment.get_coredata().prefix)
-            ofile.write('libdir=${prefix}/%s\n' % self.environment.get_coredata().libdir)
-            ofile.write('includedir=${prefix}/%s\n\n' % self.environment.get_coredata().includedir)
+            coredata = self.environment.get_coredata()
+            ofile.write('prefix=%s\n' % coredata.get_builtin_option('prefix'))
+            ofile.write('libdir=${prefix}/%s\n' % coredata.get_builtin_option('libdir'))
+            ofile.write('includedir=${prefix}/%s\n\n' % coredata.get_builtin_option('includedir'))
             ofile.write('Name: %s\n' % p.name)
             if len(p.description) > 0:
                 ofile.write('Description: %s\n' % p.description)
diff --git a/compilers.py b/compilers.py
index 85b57b320..862a4f062 100644
--- a/compilers.py
+++ b/compilers.py
@@ -17,6 +17,7 @@ import tempfile
 import mesonlib
 import mlog
 from coredata import MesonException
+import coredata
 
 """This file contains the data files of all compilers Meson knows
 about. To support a new compiler, add its information below.
@@ -1017,7 +1018,7 @@ class VisualStudioCCompiler(CCompiler):
         return []
 
     def get_options(self):
-        return {'c_winlibs' : mesonlib.UserStringArrayOption('c_winlibs',
+        return {'c_winlibs' : coredata.UserStringArrayOption('c_winlibs',
                                                              'Windows libs to link against.',
                                                              msvc_winlibs)
                 }
@@ -1056,11 +1057,11 @@ class VisualStudioCPPCompiler(VisualStudioCCompiler):
             raise EnvironmentException('Executables created by C++ compiler %s are not runnable.' % self.name_string())
 
     def get_options(self):
-        return {'cpp_eh' : mesonlib.UserComboOption('cpp_eh',
+        return {'cpp_eh' : coredata.UserComboOption('cpp_eh',
                                                     'C++ exception handling type.',
                                                     ['none', 'a', 's', 'sc'],
                                                     'sc'),
-                'cpp_winlibs' : mesonlib.UserStringArrayOption('cpp_winlibs',
+                'cpp_winlibs' : coredata.UserStringArrayOption('cpp_winlibs',
                                                                'Windows libs to link against.',
                                                                msvc_winlibs)
                 }
@@ -1129,12 +1130,12 @@ class GnuCCompiler(CCompiler):
         return super().can_compile(filename) or filename.split('.')[-1].lower() == 's' # Gcc can do asm, too.
 
     def get_options(self):
-        opts = {'c_std' : mesonlib.UserComboOption('c_std', 'C language standard to use',
+        opts = {'c_std' : coredata.UserComboOption('c_std', 'C language standard to use',
                                                    ['none', 'c89', 'c99', 'c11', 'gnu89', 'gnu99', 'gnu11'],
                                                    'c11')}
         if self.gcc_type == GCC_MINGW:
             opts.update({
-                'c_winlibs': mesonlib.UserStringArrayOption('c_winlibs', 'Standard Win libraries to link against',
+                'c_winlibs': coredata.UserStringArrayOption('c_winlibs', 'Standard Win libraries to link against',
                                                             gnu_winlibs),
                 })
         return opts
@@ -1240,7 +1241,7 @@ class ClangCCompiler(CCompiler):
         return ['-include-pch', os.path.join (pch_dir, self.get_pch_name (header))]
 
     def get_options(self):
-        return {'c_std' : mesonlib.UserComboOption('c_std', 'C language standard to use',
+        return {'c_std' : coredata.UserComboOption('c_std', 'C language standard to use',
                                                    ['none', 'c89', 'c99', 'c11'],
                                                    'c11')}
 
@@ -1282,12 +1283,12 @@ class GnuCPPCompiler(CPPCompiler):
         return get_gcc_soname_args(self.gcc_type, shlib_name, path, soversion)
 
     def get_options(self):
-        opts = {'cpp_std' : mesonlib.UserComboOption('cpp_std', 'C language standard to use',
+        opts = {'cpp_std' : coredata.UserComboOption('cpp_std', 'C language standard to use',
                                                      ['none', 'c++03', 'c++11', 'c++1y'],
                                                      'c++11')}
         if self.gcc_type == GCC_MINGW:
             opts.update({
-                'cpp_winlibs': mesonlib.UserStringArrayOption('c_winlibs', 'Standard Win libraries to link against',
+                'cpp_winlibs': coredata.UserStringArrayOption('c_winlibs', 'Standard Win libraries to link against',
                                                               gnu_winlibs),
                 })
         return opts
@@ -1328,7 +1329,7 @@ class ClangCPPCompiler(CPPCompiler):
         return ['-include-pch', os.path.join (pch_dir, self.get_pch_name (header))]
 
     def get_options(self):
-        return {'cpp_std' : mesonlib.UserComboOption('cpp_std', 'C++ language standard to use',
+        return {'cpp_std' : coredata.UserComboOption('cpp_std', 'C++ language standard to use',
                                                    ['none', 'c++03', 'c++11', 'c++1y'],
                                                    'c++11')}
 
diff --git a/coredata.py b/coredata.py
index 711dddf8b..b1a9919f0 100644
--- a/coredata.py
+++ b/coredata.py
@@ -16,6 +16,11 @@ import pickle, os, uuid
 
 version = '0.27.0-research'
 
+build_types = ['plain', 'debug', 'debugoptimized', 'release']
+layouts = ['mirror', 'flat']
+warning_levels = ['1', '2', '3']
+libtypelist = ['shared', 'static']
+
 builtin_options = {'buildtype': True,
                    'strip': True,
                    'coverage': True,
@@ -31,8 +36,98 @@ builtin_options = {'buildtype': True,
                    'werror' : True,
                    'warning_level': True,
                    'layout' : True,
+                   'default_library': True,
                   }
 
+class MesonException(Exception):
+    def __init__(self, *args, **kwargs):
+        Exception.__init__(self, *args, **kwargs)
+
+class UserOption:
+    def __init__(self, name, description):
+        super().__init__()
+        self.name = name
+        self.description = description
+
+    def parse_string(self, valuestring):
+        return valuestring
+
+class UserStringOption(UserOption):
+    def __init__(self, name, description, value):
+        super().__init__(name, description)
+        self.set_value(value)
+
+    def validate(self, value):
+        if not isinstance(value, str):
+            raise MesonException('Value "%s" for string option "%s" is not a string.' % (str(newvalue), self.name))
+        if self.name == 'prefix' and not os.path.isabs(value):
+            raise MesonException('Prefix option must be an absolute path.')
+        if self.name in ('libdir', 'bindir', 'includedir', 'datadir', 'mandir', 'localedir') \
+            and os.path.isabs(value):
+            raise MesonException('Option %s must not be an absolute path.' % self.name)
+
+    def set_value(self, newvalue):
+        self.validate(newvalue)
+        self.value = newvalue
+
+class UserBooleanOption(UserOption):
+    def __init__(self, name, description, value):
+        super().__init__(name, description)
+        self.set_value(value)
+
+    def tobool(self, thing):
+        if isinstance(thing, bool):
+            return thing
+        if thing.lower() == 'true':
+            return True
+        if thing.lower() == 'false':
+            return False
+        raise MesonException('Value %s is not boolean (true or false).' % thing)
+
+    def set_value(self, newvalue):
+        self.value = self.tobool(newvalue)
+
+    def parse_string(self, valuestring):
+        if valuestring == 'false':
+            return False
+        if valuestring == 'true':
+            return True
+        raise MesonException('Value "%s" for boolean option "%s" is not a boolean.' % (valuestring, self.name))
+
+class UserComboOption(UserOption):
+    def __init__(self, name, description, choices, value):
+        super().__init__(name, description)
+        self.choices = choices
+        if not isinstance(self.choices, list):
+            raise MesonException('Combo choices must be an array.')
+        for i in self.choices:
+            if not isinstance(i, str):
+                raise MesonException('Combo choice elements must be strings.')
+        self.set_value(value)
+
+    def set_value(self, newvalue):
+        if newvalue not in self.choices:
+            optionsstring = ', '.join(['"%s"' % (item,) for item in self.choices])
+            raise MesonException('Value "%s" for combo option "%s" is not one of the choices. Possible choices are: %s.' % (newvalue, self.name, optionsstring))
+        self.value = newvalue
+
+class UserStringArrayOption(UserOption):
+    def __init__(self, name, description, value):
+        super().__init__(name, description)
+        self.set_value(value)
+
+    def set_value(self, newvalue):
+        if isinstance(newvalue, str):
+            if not newvalue.startswith('['):
+                raise MesonException('Valuestring does not define an array: ' + newvalue)
+            newvalue = eval(newvalue, {}, {}) # Yes, it is unsafe.
+        if not isinstance(newvalue, list):
+            raise MesonException('String array value is not an array.')
+        for i in newvalue:
+            if not isinstance(i, str):
+                raise MesonException('String array element not a string.')
+        self.value = newvalue
+
 # This class contains all data that must persist over multiple
 # invocations of Meson. It is roughly the same thing as
 # cmakecache.
@@ -45,22 +140,8 @@ class CoreData():
         self.regen_guid = str(uuid.uuid4()).upper()
         self.target_guids = {}
         self.version = version
-        self.prefix = options.prefix
-        self.libdir = options.libdir
-        self.bindir = options.bindir
-        self.includedir = options.includedir
-        self.datadir = options.datadir
-        self.mandir = options.mandir
-        self.localedir = options.localedir
-        self.backend = options.backend
-        self.buildtype = options.buildtype
-        self.strip = options.strip
-        self.use_pch = options.use_pch
-        self.unity = options.unity
-        self.coverage = options.coverage
-        self.warning_level = options.warning_level
-        self.werror = options.werror
-        self.layout = options.layout
+        self.builtin_options = {}
+        self.init_builtins(options)
         self.user_options = {}
         self.compiler_options = {}
         self.external_args = {} # These are set from "the outside" with e.g. mesonconf
@@ -77,35 +158,39 @@ class CoreData():
         self.ext_libs = {}
         self.modules = {}
 
+    def init_builtins(self, options):
+        self.builtin_options['prefix'] = UserStringOption('prefix', 'Installation prefix', options.prefix)
+        self.builtin_options['libdir'] = UserStringOption('libdir', 'Library dir', options.libdir)
+        self.builtin_options['bindir'] = UserStringOption('bindir', 'Executable dir', options.bindir)
+        self.builtin_options['includedir'] = UserStringOption('includedir', 'Include dir', options.includedir)
+        self.builtin_options['datadir'] = UserStringOption('datadir', 'Data directory', options.datadir)
+        self.builtin_options['mandir'] = UserStringOption('mandir', 'Man page dir', options.mandir)
+        self.builtin_options['localedir'] = UserStringOption('localedir', 'Locale dir', options.localedir)
+        self.builtin_options['backend'] = UserStringOption('backend', 'Backend to use', options.backend)
+        self.builtin_options['buildtype'] = UserComboOption('buildtype', 'Build type', build_types, options.buildtype)
+        self.builtin_options['strip'] = UserBooleanOption('strip', 'Strip on install', options.strip)
+        self.builtin_options['use_pch'] = UserBooleanOption('use_pch', 'Use precompiled headers', options.use_pch)
+        self.builtin_options['unity'] = UserBooleanOption('unity', 'Unity build', options.unity)
+        self.builtin_options['coverage'] = UserBooleanOption('coverage', 'Enable coverage', options.coverage)
+        self.builtin_options['warning_level'] = UserComboOption('warning_level', 'Warning level', warning_levels, options.warning_level)
+        self.builtin_options['werror'] = UserBooleanOption('werror', 'Warnings are errors', options.werror)
+        self.builtin_options['layout'] = UserComboOption('layout', 'Build dir layout', layouts, options.layout)
+        self.builtin_options['default_library'] = UserComboOption('default_library', 'Default_library type', libtypelist, options.default_library)
+
     def get_builtin_option(self, optname):
-        if optname == 'buildtype':
-            return self.buildtype
-        if optname == 'strip':
-            return self.strip
-        if optname == 'coverage':
-            return self.coverage
-        if optname == 'pch':
-            return self.use_pch
-        if optname == 'unity':
-            return self.unity
-        if optname == 'prefix':
-            return self.prefix
-        if optname == 'libdir':
-            return self.libdir
-        if optname == 'bindir':
-            return self.bindir
-        if optname == 'includedir':
-            return self.includedir
-        if optname == 'datadir':
-            return self.datadir
-        if optname == 'mandir':
-            return self.mandir
-        if optname == 'localedir':
-            return self.localedir
-        if optname == 'layout':
-            return self.layout
+        if optname in self.builtin_options:
+            return self.builtin_options[optname].value
         raise RuntimeError('Tried to get unknown builtin option %s' % optname)
 
+    def set_builtin_option(self, optname, value):
+        if optname in self.builtin_options:
+            self.builtin_options[optname].set_value(value)
+        else:
+            raise RuntimeError('Tried to set unknown builtin option %s' % optname)
+
+    def is_builtin_option(self, optname):
+        return optname in self.builtin_options
+
 def load(filename):
     obj = pickle.load(open(filename, 'rb'))
     if not isinstance(obj, CoreData):
@@ -134,7 +219,3 @@ forbidden_target_names = {'clean': None,
                           'install': None,
                           'build.ninja': None,
                          }
-
-class MesonException(Exception):
-    def __init__(self, *args, **kwargs):
-        Exception.__init__(self, *args, **kwargs)
diff --git a/environment.py b/environment.py
index c4878f447..697957dee 100644
--- a/environment.py
+++ b/environment.py
@@ -543,22 +543,22 @@ class Environment():
         return self.object_suffix
 
     def get_prefix(self):
-        return self.coredata.prefix
+        return self.coredata.get_builtin_option('prefix')
 
     def get_libdir(self):
-        return self.coredata.libdir
+        return self.coredata.get_builtin_option('libdir')
 
     def get_bindir(self):
-        return self.coredata.bindir
+        return self.coredata.get_builtin_option('bindir')
 
     def get_includedir(self):
-        return self.coredata.includedir
+        return self.coredata.get_builtin_option('includedir')
 
     def get_mandir(self):
-        return self.coredata.mandir
+        return self.coredata.get_builtin_option('mandir')
 
     def get_datadir(self):
-        return self.coredata.datadir
+        return self.coredata.get_builtin_option('datadir')
 
     def find_library(self, libname, dirs):
         if dirs is None:
diff --git a/interpreter.py b/interpreter.py
index 507694136..f71d7f51d 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -855,7 +855,7 @@ class MesonMain(InterpreterObject):
         raise InterpreterException('Tried to access compiler for unspecified language "%s".' % cname)
 
     def is_unity_method(self, args, kwargs):
-        return self.build.environment.coredata.unity
+        return self.build.environment.coredata.get_builtin_option('unity')
 
     def is_subproject_method(self, args, kwargs):
         return self.interpreter.is_subproject()
@@ -933,6 +933,7 @@ class Interpreter():
                       'dependency' : self.func_dependency,
                       'static_library' : self.func_static_lib,
                       'shared_library' : self.func_shared_lib,
+                      'library' : self.func_library,
                       'jar' : self.func_jar,
                       'build_target': self.func_build_target,
                       'custom_target' : self.func_custom_target,
@@ -1351,9 +1352,10 @@ class Interpreter():
             if '=' not in option:
                 raise InterpreterException('All default options must be of type key=value.')
             key, value = option.split('=', 1)
-            if hasattr(self.coredata, key):
+            builtin_options = self.coredata.builtin_options
+            if key in builtin_options:
                 if not hasattr(self.environment.cmd_line_options, value):
-                    setattr(self.coredata, key, value)
+                    self.coredata.set_builtin_option(key, value)
                 # If this was set on the command line, do not override.
             else:
                 newoptions = [option] + self.environment.cmd_line_options.projectoptions
@@ -1579,6 +1581,11 @@ class Interpreter():
     def func_shared_lib(self, node, args, kwargs):
         return self.build_target(node, args, kwargs, SharedLibraryHolder)
 
+    def func_library(self, node, args, kwargs):
+        if self.coredata.get_builtin_option('default_library') == 'shared':
+            return self.func_shared_lib(node, args, kwargs)
+        return self.func_static_lib(node, args, kwargs)
+
     def func_jar(self, node, args, kwargs):
         return self.build_target(node, args, kwargs, JarHolder)
 
@@ -1592,6 +1599,8 @@ class Interpreter():
             return self.func_shared_lib(node, args, kwargs)
         elif target_type == 'static_library':
             return self.func_static_lib(node, args, kwargs)
+        elif target_type == 'library':
+            return self.func_library(node, args, kwargs)
         elif target_type == 'jar':
             return self.func_jar(node, args, kwargs)
         else:
@@ -2021,7 +2030,7 @@ class Interpreter():
         else:
             obj = self.evaluate_statement(invokable)
         method_name = node.name
-        if method_name == 'extract_objects' and self.environment.coredata.unity:
+        if method_name == 'extract_objects' and self.environment.coredata.get_builtin_option('unity'):
             raise InterpreterException('Single object files can not be extracted in Unity builds.')
         args = node.args
         if isinstance(obj, mparser.StringNode):
diff --git a/meson.py b/meson.py
index 4c8e171e6..1720117b2 100755
--- a/meson.py
+++ b/meson.py
@@ -22,14 +22,11 @@ import build
 import platform
 import mlog, coredata
 
-from coredata import MesonException
-
-parser = argparse.ArgumentParser()
+from coredata import MesonException, build_types, layouts, warning_levels, libtypelist
 
 backendlist = ['ninja', 'vs2010', 'xcode']
-build_types = ['plain', 'debug', 'debugoptimized', 'release']
-layouts = ['mirror', 'flat']
-warning_levels = ['1', '2', '3']
+
+parser = argparse.ArgumentParser()
 
 default_warning = '2'
 
@@ -68,6 +65,8 @@ parser.add_argument('--werror', action='store_true', dest='werror', default=Fals
                     help='Treat warnings as errors')
 parser.add_argument('--layout', choices=layouts, dest='layout', default='mirror',\
                     help='Build directory layout.')
+parser.add_argument('--default-library', choices=libtypelist, dest='default_library',
+                    default='shared', help='Default library type.')
 parser.add_argument('--warnlevel', default=default_warning, dest='warning_level', choices=warning_levels,\
                     help='Level of compiler warnings to use (larger is more, default is %(default)s)')
 parser.add_argument('--cross-file', default=None, dest='cross_file',
diff --git a/mesonconf.py b/mesonconf.py
index 963585ad4..14fd8f4f5 100755
--- a/mesonconf.py
+++ b/mesonconf.py
@@ -26,7 +26,7 @@ parser.add_argument('-D', action='append', default=[], dest='sets',
                     help='Set an option to the given value.')
 parser.add_argument('directory', nargs='*')
 
-class ConfException(Exception):
+class ConfException(coredata.MesonException):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
 
@@ -69,55 +69,8 @@ class Conf:
             if '=' not in o:
                 raise ConfException('Value "%s" not of type "a=b".' % o)
             (k, v) = o.split('=', 1)
-            if k == 'buildtype':
-                if v not in build_types:
-                    raise ConfException('Invalid build type %s.' % v)
-                self.coredata.buildtype = v
-            elif k == 'layout':
-                if v not in layouts:
-                    raise ConfException('Invalid layout type %s.' % v)
-                self.coredata.layout = v
-            elif k == 'warnlevel':
-                if not v in warning_levels:
-                    raise ConfException('Invalid warning level %s.' % v)
-                self.coredata.warning_level = v
-            elif k == 'strip':
-                self.coredata.strip = self.tobool(v)
-            elif k == 'coverage':
-                v = self.tobool(v)
-                self.coredata.coverage = self.tobool(v)
-            elif k == 'pch':
-                self.coredata.use_pch = self.tobool(v)
-            elif k == 'unity':
-                self.coredata.unity = self.tobool(v)
-            elif k == 'prefix':
-                if not os.path.isabs(v):
-                    raise ConfException('Install prefix %s is not an absolute path.' % v)
-                self.coredata.prefix = v
-            elif k == 'libdir':
-                if os.path.isabs(v):
-                    raise ConfException('Library dir %s must not be an absolute path.' % v)
-                self.coredata.libdir = v
-            elif k == 'bindir':
-                if os.path.isabs(v):
-                    raise ConfException('Binary dir %s must not be an absolute path.' % v)
-                self.coredata.bindir = v
-            elif k == 'includedir':
-                if os.path.isabs(v):
-                    raise ConfException('Include dir %s must not be an absolute path.' % v)
-                self.coredata.includedir = v
-            elif k == 'datadir':
-                if os.path.isabs(v):
-                    raise ConfException('Data dir %s must not be an absolute path.' % v)
-                self.coredata.datadir = v
-            elif k == 'mandir':
-                if os.path.isabs(v):
-                    raise ConfException('Man dir %s must not be an absolute path.' % v)
-                self.coredata.mandir = v
-            elif k == 'localedir':
-                if os.path.isabs(v):
-                    raise ConfException('Locale dir %s must not be an absolute path.' % v)
-                self.coredata.localedir = v
+            if self.coredata.is_builtin_option(k):
+                self.coredata.set_builtin_option(k, v)
             elif k in self.coredata.user_options:
                 tgt = self.coredata.user_options[k]
                 tgt.set_value(v)
@@ -150,12 +103,13 @@ class Conf:
         print('')
         print('Core options\n')
         carr = []
-        carr.append(['buildtype', 'Build type', self.coredata.buildtype])
-        carr.append(['warnlevel', 'Warning level', self.coredata.warning_level])
-        carr.append(['strip', 'Strip on install', self.coredata.strip])
-        carr.append(['coverage', 'Coverage report', self.coredata.coverage])
-        carr.append(['pch', 'Precompiled headers', self.coredata.use_pch])
-        carr.append(['unity', 'Unity build', self.coredata.unity])
+        carr.append(['buildtype', 'Build type', self.coredata.get_builtin_option('buildtype')])
+        carr.append(['warning_level', 'Warning level', self.coredata.get_builtin_option('warning_level')])
+        carr.append(['strip', 'Strip on install', self.coredata.get_builtin_option('strip')])
+        carr.append(['coverage', 'Coverage report', self.coredata.get_builtin_option('coverage')])
+        carr.append(['use_pch', 'Precompiled headers', self.coredata.get_builtin_option('use_pch')])
+        carr.append(['unity', 'Unity build', self.coredata.get_builtin_option('unity')])
+        carr.append(['default_library', 'Default library type', self.coredata.get_builtin_option('default_library')])
         self.print_aligned(carr)
         print('')
         print('Compiler arguments\n')
@@ -179,13 +133,13 @@ class Conf:
         print('')
         print('Directories\n')
         parr = []
-        parr.append(['prefix', 'Install prefix', self.coredata.prefix])
-        parr.append(['libdir', 'Library directory', self.coredata.libdir])
-        parr.append(['bindir', 'Binary directory', self.coredata.bindir])
-        parr.append(['includedir', 'Header directory', self.coredata.includedir])
-        parr.append(['datadir', 'Data directory', self.coredata.datadir])
-        parr.append(['mandir', 'Man page directory', self.coredata.mandir])
-        parr.append(['localedir', 'Locale file directory', self.coredata.localedir])
+        parr.append(['prefix', 'Install prefix', self.coredata.get_builtin_option('prefix')])
+        parr.append(['libdir', 'Library directory', self.coredata.get_builtin_option('libdir')])
+        parr.append(['bindir', 'Binary directory', self.coredata.get_builtin_option('bindir')])
+        parr.append(['includedir', 'Header directory', self.coredata.get_builtin_option('includedir')])
+        parr.append(['datadir', 'Data directory', self.coredata.get_builtin_option('datadir')])
+        parr.append(['mandir', 'Man page directory', self.coredata.get_builtin_option('mandir')])
+        parr.append(['localedir', 'Locale file directory', self.coredata.get_builtin_option('localedir')])
         self.print_aligned(parr)
         print('')
         if len(self.coredata.user_options) == 0:
@@ -218,7 +172,7 @@ if __name__ == '__main__':
             c.save()
         else:
             c.print_conf()
-    except ConfException as e:
+    except coredata.MesonException as e:
         print('Meson configurator encountered an error:\n')
         print(e)
 
diff --git a/mesonlib.py b/mesonlib.py
index f42209534..bb69632db 100644
--- a/mesonlib.py
+++ b/mesonlib.py
@@ -264,80 +264,3 @@ def stringlistify(item):
         if not isinstance(i, str):
             raise MesonException('List item not a string.')
     return item
-
-class UserOption:
-    def __init__(self, name, description):
-        super().__init__()
-        self.name = name
-        self.description = description
-
-    def parse_string(self, valuestring):
-        return valuestring
-
-class UserStringOption(UserOption):
-    def __init__(self, name, description, value):
-        super().__init__(name, description)
-        self.set_value(value)
-
-    def set_value(self, newvalue):
-        if not isinstance(newvalue, str):
-            raise MesonException('Value "%s" for string option "%s" is not a string.' % (str(newvalue), self.name))
-        self.value = newvalue
-
-class UserBooleanOption(UserOption):
-    def __init__(self, name, description, value):
-        super().__init__(name, description)
-        self.set_value(value)
-
-    def tobool(self, thing):
-        if isinstance(thing, bool):
-            return thing
-        if thing.lower() == 'true':
-            return True
-        if thing.lower() == 'false':
-            return False
-        raise MesonException('Value %s is not boolean (true or false).' % thing)
-
-    def set_value(self, newvalue):
-        self.value = self.tobool(newvalue)
-
-    def parse_string(self, valuestring):
-        if valuestring == 'false':
-            return False
-        if valuestring == 'true':
-            return True
-        raise MesonException('Value "%s" for boolean option "%s" is not a boolean.' % (valuestring, self.name))
-
-class UserComboOption(UserOption):
-    def __init__(self, name, description, choices, value):
-        super().__init__(name, description)
-        self.choices = choices
-        if not isinstance(self.choices, list):
-            raise MesonException('Combo choices must be an array.')
-        for i in self.choices:
-            if not isinstance(i, str):
-                raise MesonException('Combo choice elements must be strings.')
-        self.set_value(value)
-
-    def set_value(self, newvalue):
-        if newvalue not in self.choices:
-            optionsstring = ', '.join(['"%s"' % (item,) for item in self.choices])
-            raise MesonException('Value "%s" for combo option "%s" is not one of the choices. Possible choices are: %s.' % (newvalue, self.name, optionsstring))
-        self.value = newvalue
-
-class UserStringArrayOption(UserOption):
-    def __init__(self, name, description, value):
-        super().__init__(name, description)
-        self.set_value(value)
-
-    def set_value(self, newvalue):
-        if isinstance(newvalue, str):
-            if not newvalue.startswith('['):
-                raise MesonException('Valuestring does not define an array: ' + newvalue)
-            newvalue = eval(newvalue, {}, {}) # Yes, it is unsafe.
-        if not isinstance(newvalue, list):
-            raise MesonException('String array value is not an array.')
-        for i in newvalue:
-            if not isinstance(i, str):
-                raise MesonException('String array element not a string.')
-        self.value = newvalue
diff --git a/ninjabackend.py b/ninjabackend.py
index f1274a74c..9081736ee 100644
--- a/ninjabackend.py
+++ b/ninjabackend.py
@@ -150,7 +150,7 @@ class NinjaBackend(backends.Backend):
         self.generate_tests(outfile)
         outfile.write('# Install rules\n\n')
         self.generate_install(outfile)
-        if self.environment.coredata.coverage:
+        if self.environment.coredata.get_builtin_option('coverage'):
             outfile.write('# Coverage rules\n\n')
             self.generate_coverage_rules(outfile)
         outfile.write('# Suffix\n\n')
@@ -203,8 +203,8 @@ class NinjaBackend(backends.Backend):
         self.generate_custom_generator_rules(target, outfile)
         outname = self.get_target_filename(target)
         obj_list = []
-        use_pch = self.environment.coredata.use_pch
-        is_unity = self.environment.coredata.unity
+        use_pch = self.environment.coredata.get_builtin_option('use_pch')
+        is_unity = self.environment.coredata.get_builtin_option('unity')
         if use_pch and target.has_pch():
             pch_objects = self.generate_pch(target, outfile)
         else:
@@ -444,14 +444,14 @@ class NinjaBackend(backends.Backend):
             for lang in languages:
                 rel_src =  os.path.join(subdir, lang + '.gmo')
                 src_file = os.path.join(self.environment.get_build_dir(), rel_src)
-                d.po.append((src_file, self.environment.coredata.localedir, lang))
+                d.po.append((src_file, self.environment.coredata.get_builtin_option('localedir'), lang))
                 elem.add_dep(rel_src)
 
     def generate_target_install(self, d):
         libdir = self.environment.get_libdir()
         bindir = self.environment.get_bindir()
 
-        should_strip = self.environment.coredata.strip
+        should_strip = self.environment.coredata.get_builtin_option('strip')
         for t in self.build.get_targets().values():
             if t.should_install():
                 outdir = t.get_custom_install_dir()
@@ -465,7 +465,7 @@ class NinjaBackend(backends.Backend):
                 d.targets.append(i)
 
     def generate_pkgconfig_install(self, d):
-        pkgroot = os.path.join(self.environment.coredata.libdir, 'pkgconfig')
+        pkgroot = os.path.join(self.environment.coredata.get_builtin_option('libdir'), 'pkgconfig')
 
         for p in self.build.pkgconfig_gens:
             pcfile = p.filebase + '.pc'
@@ -647,7 +647,7 @@ class NinjaBackend(backends.Backend):
         return (args, deps)
 
     def generate_cs_target(self, target, outfile):
-        buildtype = self.environment.coredata.buildtype
+        buildtype = self.environment.coredata.get_builtin_option('buildtype')
         fname = target.get_filename()
         outname_rel = os.path.join(self.get_target_dir(target), fname)
         src_list = target.get_sources()
@@ -683,7 +683,7 @@ class NinjaBackend(backends.Backend):
 
     def generate_single_java_compile(self, src, target, compiler, outfile):
         args = []
-        args += compiler.get_buildtype_args(self.environment.coredata.buildtype)
+        args += compiler.get_buildtype_args(self.environment.coredata.get_builtin_option('buildtype'))
         args += compiler.get_output_args(self.get_target_private_dir(target))
         rel_src = src.rel_to_builddir(self.build_to_src)
         plain_class_path = src.fname[:-4] + 'class'
@@ -753,7 +753,7 @@ class NinjaBackend(backends.Backend):
             relsc = os.path.join(self.get_target_private_dir_abs(target), sc)
             rel_s = s.rel_to_builddir(self.build_to_src)
             args += ['--deps', relsc + '.d']
-            if self.environment.coredata.werror:
+            if self.environment.coredata.get_builtin_option('werror'):
                 args += valac.get_werror_args()
             for d in target.external_deps:
                 if isinstance(d, dependencies.PkgConfigDependency):
@@ -1257,7 +1257,7 @@ rule FORTRAN_DEP_HACK
         rel_obj = os.path.join(self.get_target_private_dir(target), obj_basename)
         rel_obj += '.' + self.environment.get_object_suffix()
         dep_file = rel_obj + '.' + compiler.get_depfile_suffix()
-        if self.environment.coredata.use_pch:
+        if self.environment.coredata.get_builtin_option('use_pch'):
             pchlist = target.get_pch(compiler.language)
         else:
             pchlist = []
@@ -1287,7 +1287,7 @@ rule FORTRAN_DEP_HACK
                     custom_target_include_dirs.append(idir)
         for i in custom_target_include_dirs:
             commands+= compiler.get_include_args(i)
-        if self.environment.coredata.use_pch:
+        if self.environment.coredata.get_builtin_option('use_pch'):
             commands += self.get_pch_include_args(compiler, target)
         crstr = ''
         if target.is_cross:
@@ -1425,7 +1425,7 @@ rule FORTRAN_DEP_HACK
         abspath = os.path.join(self.environment.get_build_dir(), target.subdir)
         commands = []
         commands += linker.get_linker_always_args()
-        commands += linker.get_buildtype_linker_args(self.environment.coredata.buildtype)
+        commands += linker.get_buildtype_linker_args(self.environment.coredata.get_builtin_option('buildtype'))
         commands += linker.get_option_link_args(self.environment.coredata.compiler_options)
         if not(isinstance(target, build.StaticLibrary)):
             commands += self.environment.coredata.external_link_args[linker.get_language()]
@@ -1465,7 +1465,7 @@ rule FORTRAN_DEP_HACK
                         commands += dep.get_link_args()
         commands += linker.build_rpath_args(self.environment.get_build_dir(),\
                                             self.determine_rpath_dirs(target), target.install_rpath)
-        if self.environment.coredata.coverage:
+        if self.environment.coredata.get_builtin_option('coverage'):
             commands += linker.get_coverage_link_args()
         commands += extra_args
         dep_targets = [self.get_dependency_filename(t) for t in dependencies]
@@ -1570,7 +1570,7 @@ rule FORTRAN_DEP_HACK
         elem = NinjaBuildElement('clean', 'CUSTOM_COMMAND', 'PHONY')
         elem.add_item('COMMAND', [ninja_command, '-t', 'clean'])
         elem.add_item('description', 'Cleaning')
-        if self.environment.coredata.coverage:
+        if self.environment.coredata.get_builtin_option('coverage'):
             self.generate_gcov_clean(outfile)
             elem.add_dep('clean-gcda')
             elem.add_dep('clean-gcno')
diff --git a/optinterpreter.py b/optinterpreter.py
index d66aa1f32..f10632630 100644
--- a/optinterpreter.py
+++ b/optinterpreter.py
@@ -40,11 +40,11 @@ class OptionException(coredata.MesonException):
 optname_regex = re.compile('[^a-zA-Z0-9_-]')
 
 def StringParser(name, description, kwargs):
-    return mesonlib.UserStringOption(name, description,
+    return coredata.UserStringOption(name, description,
                                      kwargs.get('value', ''))
 
 def BooleanParser(name, description, kwargs):
-    return mesonlib.UserBooleanOption(name, description, kwargs.get('value', True))
+    return coredata.UserBooleanOption(name, description, kwargs.get('value', True))
 
 def ComboParser(name, description, kwargs):
     if 'choices' not in kwargs:
@@ -55,7 +55,7 @@ def ComboParser(name, description, kwargs):
     for i in choices:
         if not isinstance(i, str):
             raise OptionException('Combo choice elements must be strings.')
-    return mesonlib.UserComboOption(name, description, choices, kwargs.get('value', choices[0]))
+    return coredata.UserComboOption(name, description, choices, kwargs.get('value', choices[0]))
 
 option_types = {'string' : StringParser,
                 'boolean' : BooleanParser,
diff --git a/test cases/common/96 default library/ef.cpp b/test cases/common/96 default library/ef.cpp
new file mode 100644
index 000000000..79983c6bd
--- /dev/null
+++ b/test cases/common/96 default library/ef.cpp	
@@ -0,0 +1,8 @@
+#include"ef.h"
+
+Ef::Ef() : x(99) {
+}
+
+int Ef::get_x() const {
+    return x;
+}
diff --git a/test cases/common/96 default library/ef.h b/test cases/common/96 default library/ef.h
new file mode 100644
index 000000000..cae5c1392
--- /dev/null
+++ b/test cases/common/96 default library/ef.h	
@@ -0,0 +1,11 @@
+#pragma once
+
+class Ef {
+private:
+    int x;
+
+public:
+
+    Ef();
+    int get_x() const;
+};
diff --git a/test cases/common/96 default library/eftest.cpp b/test cases/common/96 default library/eftest.cpp
new file mode 100644
index 000000000..4d4412d75
--- /dev/null
+++ b/test cases/common/96 default library/eftest.cpp	
@@ -0,0 +1,14 @@
+#include"ef.h"
+
+#include<iostream>
+
+int main(int, char **) {
+    Ef var;
+    if(var.get_x() == 99) {
+        std::cout << "All is fine.\n";
+        return 0;
+    } else {
+        std::cout << "Something went wrong.\n";
+        return 1;
+    }
+}
diff --git a/test cases/common/96 default library/meson.build b/test cases/common/96 default library/meson.build
new file mode 100644
index 000000000..903cfe40a
--- /dev/null
+++ b/test cases/common/96 default library/meson.build	
@@ -0,0 +1,5 @@
+project('default library', 'cpp')
+
+flib = library('ef', 'ef.cpp')
+exe = executable('eftest', 'eftest.cpp', link_with : flib)
+test('eftest', exe)