optinterpreter: Remove duplicated list of languages

It is important to keep the list of languages up to date in
optinterpreter, otherwise we could have conflicting options when adding
new languages.

mesonbuild/compilers/__init__.py

@@ -25,6 +25,7 @@ __all__ = [
     'ICC_STANDARD',
     'ICC_WIN',
 
+    'all_languages',
     'base_options',
     'clike_langs',
     'c_suffixes',
@@ -99,6 +100,7 @@ from .compilers import (
     ICC_OSX,
     ICC_WIN,
     ICC_STANDARD,
+    all_languages,
     base_options,
     clike_langs,
     c_suffixes,

mesonbuild/compilers/compilers.py

@@ -45,6 +45,7 @@ lang_suffixes = {
     'swift': ('swift',),
     'java': ('java',),
 }
+all_languages = lang_suffixes.keys()
 cpp_suffixes = lang_suffixes['cpp'] + ('h',)
 c_suffixes = lang_suffixes['c'] + ('h',)
 # List of languages that can be linked with C code directly by the linker

mesonbuild/optinterpreter.py

@@ -20,21 +20,10 @@ from . import mparser
 from . import coredata
 from . import mesonlib
 from .interpreterbase import FeatureNew
+from . import compilers
 
 forbidden_option_names = coredata.get_builtin_options()
-forbidden_prefixes = {'c_',
-                      'cpp_',
-                      'd_',
-                      'rust_',
-                      'fortran_',
-                      'objc_',
-                      'objcpp_',
-                      'vala_',
-                      'csharp_',
-                      'swift_',
-                      'b_',
-                      'backend_',
-                      }
+forbidden_prefixes = [lang + '_' for lang in compilers.all_languages] + ['b_', 'backend_']
 
 def is_invalid_name(name):
     if name in forbidden_option_names: