allow paths to be set in the cross file

Just like the previous patch, but for cross files

Fixes #1433

docs/markdown/Cross-compilation.md

@@ -150,7 +150,7 @@ binaries are not actually compatible. In such cases you may use the
 needs_exe_wrapper = true
 ```
 
-The last bit is the definition of host and target machines. Every
+The next bit is the definition of host and target machines. Every
 cross build definition must have one or both of them. If it had
 neither, the build would not be a cross build but a native build. You
 do not need to define the build machine, as all necessary information
@@ -186,6 +186,20 @@ If you do not define your host machine, it is assumed to be the build
 machine. Similarly if you do not specify target machine, it is assumed
 to be the host machine.
 
+Additionally, you can define the paths that you want to install to in your
+cross file. This may be especially useful when cross compiling an entire
+operating system, or for operating systems to use internally for consistency.
+
+```ini
+[paths]
+prefix = '/my/prefix'
+libdir = 'lib/i386-linux-gnu'
+bindir = 'bin'
+```
+
+This will be overwritten by any options passed on the command line.
+
+
 ## Starting a cross build
 
 

docs/markdown/snippets/native-file-paths.md

@@ -1,4 +1,4 @@
-## Native File Paths and Directories
+## Native and Cross File Paths and Directories
 
-A new `[paths]` section has been added to the native file. This can be used to
-set paths such a prefix and libdir in a persistent way.
+A new `[paths]` section has been added to native and cross files. This
+can be used to set paths such a prefix and libdir in a persistent way.

mesonbuild/environment.py

@@ -399,6 +399,7 @@ class Environment:
                 self.machines.host = MachineInfo.from_literal(config['host_machine'])
             if 'target_machine' in config:
                 self.machines.target = MachineInfo.from_literal(config['target_machine'])
+            self.paths.host = Directories(**config.get('paths', {}))
 
         self.machines.default_missing()
         self.binaries.default_missing()

run_unittests.py

@@ -5450,6 +5450,51 @@ class NativeFileTests(BasePlatformTests):
                               '-Ddef_libdir=liblib', '-Dlibdir=liblib'])
 
 
+class CrossFileTests(BasePlatformTests):
+
+    """Tests for cross file functioality not directly related to
+    cross compiling.
+
+    This is mainly aimed to testing overrides from cross files.
+    """
+
+    def test_cross_file_dirs(self):
+        testcase = os.path.join(self.unit_test_dir, '54 native file override')
+        self.init(testcase, default_args=False,
+                  extra_args=['--native-file', os.path.join(testcase, 'nativefile'),
+                              '--cross-file', os.path.join(testcase, 'crossfile'),
+                              '-Ddef_bindir=binbar',
+                              '-Ddef_datadir=databar',
+                              '-Ddef_includedir=includebar',
+                              '-Ddef_infodir=infobar',
+                              '-Ddef_libdir=libbar',
+                              '-Ddef_libexecdir=libexecbar',
+                              '-Ddef_localedir=localebar',
+                              '-Ddef_localstatedir=localstatebar',
+                              '-Ddef_mandir=manbar',
+                              '-Ddef_sbindir=sbinbar',
+                              '-Ddef_sharedstatedir=sharedstatebar',
+                              '-Ddef_sysconfdir=sysconfbar'])
+
+    def test_cross_file_dirs_overriden(self):
+        testcase = os.path.join(self.unit_test_dir, '54 native file override')
+        self.init(testcase, default_args=False,
+                  extra_args=['--native-file', os.path.join(testcase, 'nativefile'),
+                              '--cross-file', os.path.join(testcase, 'crossfile'),
+                              '-Ddef_libdir=liblib', '-Dlibdir=liblib',
+                              '-Ddef_bindir=binbar',
+                              '-Ddef_datadir=databar',
+                              '-Ddef_includedir=includebar',
+                              '-Ddef_infodir=infobar',
+                              '-Ddef_libexecdir=libexecbar',
+                              '-Ddef_localedir=localebar',
+                              '-Ddef_localstatedir=localstatebar',
+                              '-Ddef_mandir=manbar',
+                              '-Ddef_sbindir=sbinbar',
+                              '-Ddef_sharedstatedir=sharedstatebar',
+                              '-Ddef_sysconfdir=sysconfbar'])
+
+
 def unset_envs():
     # For unit tests we must fully control all command lines
     # so that there are no unexpected changes coming from the
@@ -5468,7 +5513,7 @@ def should_run_cross_mingw_tests():
 def main():
     unset_envs()
     cases = ['InternalTests', 'DataTests', 'AllPlatformTests', 'FailureTests',
-             'PythonTests', 'NativeFileTests', 'RewriterTests']
+             'PythonTests', 'NativeFileTests', 'RewriterTests', 'CrossFileTests']
     if not is_windows():
         cases += ['LinuxlikeTests']
         if should_run_cross_arm_tests():

test cases/unit/54 native file override/crossfile

@@ -0,0 +1,16 @@
+[paths]
+bindir = 'binbar'
+datadir = 'databar'
+includedir = 'includebar'
+infodir = 'infobar'
+libdir = 'libbar'
+libexecdir = 'libexecbar'
+localedir = 'localebar'
+localstatedir = 'localstatebar'
+mandir = 'manbar'
+prefix = '/prefix'
+sbindir = 'sbinbar'
+sharedstatedir = 'sharedstatebar'
+sysconfdir = 'sysconfbar'
+
+; vim: ft=dosini