compilers: Silence warning about gnu_inline with clang

The warning is due to a change in behaviour in Clang 10 and newer:

https://releases.llvm.org/10.0.0/tools/clang/docs/ReleaseNotes.html#c-language-changes-in-clang

This was already fixed for clang++, but not for clang for some reason.
It was also fixed incorrectly; by adding `extern` instead of moving
from `-Werror` to `-Werror=attributes`.

1 files changed, 8 insertions, 3 deletions

diff --git a/mesonbuild/compilers/mixins/clike.py b/mesonbuild/compilers/mixins/clike.py
index 41848bccc..24f4796fd 100644
--- a/mesonbuild/compilers/mixins/clike.py
+++ b/mesonbuild/compilers/mixins/clike.py
@@ -1115,6 +1115,12 @@ class CLikeCompiler:
             m = pattern.match(ret)
         return ret
 
+    def get_has_func_attribute_extra_args(self, name):
+        # Most compilers (such as GCC and Clang) only warn about unknown or
+        # ignored attributes, so force an error. Overriden in GCC and Clang
+        # mixins.
+        return ['-Werror']
+
     def has_func_attribute(self, name, env):
         # Just assume that if we're not on windows that dllimport and dllexport
         # don't work
@@ -1123,6 +1129,5 @@ class CLikeCompiler:
             if name in ['dllimport', 'dllexport']:
                 return False, False
 
-        # Clang and GCC both return warnings if the __attribute__ is undefined,
-        # so set -Werror
-        return self.compiles(self.attribute_check_func(name), env, extra_args='-Werror')
+        return self.compiles(self.attribute_check_func(name), env,
+                             extra_args=self.get_has_func_attribute_extra_args(name))