coredata: encapsulate destination name

This means that there are no special args passed ot builtin args
anymore.

mesonbuild/coredata.py

@@ -367,6 +367,12 @@ def get_builtin_option_action(optname):
         return 'store_true'
     return None
 
+def get_builtin_option_destination(optname):
+    optname = optname.replace('-', '_')
+    if optname == 'warnlevel':
+        return 'warning_level'
+    return optname
+
 def get_builtin_option_default(optname, prefix='', noneIfSuppress=False):
     if is_builtin_option(optname):
         o = builtin_options[optname]

mesonbuild/mesonmain.py

@@ -26,7 +26,7 @@ from .wrap import WrapMode, wraptool
 default_warning = '1'
 
 def add_builtin_argument(p, name, **kwargs):
-    k = kwargs.get('dest', name.replace('-', '_'))
+    k = coredata.get_builtin_option_destination(name)
     c = coredata.get_builtin_option_choices(k)
     b = coredata.get_builtin_option_action(k)
     h = coredata.get_builtin_option_description(k)
@@ -65,7 +65,7 @@ def create_parser():
     add_builtin_argument(p, 'werror')
     add_builtin_argument(p, 'layout')
     add_builtin_argument(p, 'default-library')
-    add_builtin_argument(p, 'warnlevel', dest='warning_level')
+    add_builtin_argument(p, 'warnlevel')
     add_builtin_argument(p, 'stdsplit')
     add_builtin_argument(p, 'errorlogs')
     p.add_argument('--cross-file', default=None,