compilers: Check if GCC has support for ObjC and/or ObjC++

Since this is optional, we should not accept that GCC is a valid ObjC or
G++ is a valid ObjC++ Compiler unless we've tested that they can
actually do a basic compile.

This requires fixing a number of tests that have broken assumptions. In
some cases I've split tests where issues with one language would hide
the other. It would be great if we had a competent test framework that
allowed subtests to skip, unfortunately we have python's unittest
instead. Because of that we can't avoid extra tests by use of subtests.

1 files changed, 5 insertions, 1 deletions

diff --git a/mesonbuild/compilers/detect.py b/mesonbuild/compilers/detect.py
index 7bd48d10c..d4ad4bade 100644
--- a/mesonbuild/compilers/detect.py
+++ b/mesonbuild/compilers/detect.py
@@ -897,9 +897,13 @@ def _detect_objc_or_objcpp_compiler(env: 'Environment', lang: str, for_machine:
             version = _get_gnu_version_from_defines(defines)
             comp = objc.GnuObjCCompiler if lang == 'objc' else objcpp.GnuObjCPPCompiler
             linker = guess_nix_linker(env, compiler, comp, version, for_machine)
-            return comp(
+            c = comp(
                 ccache, compiler, version, for_machine, is_cross, info,
                 defines, linker=linker)
+            if not c.compiles('int main(void) { return 0; }', env)[0]:
+                popen_exceptions[join_args(compiler)] = f'GCC was not built with support for {"objective-c" if lang == "objc" else "objective-c++"}'
+                continue
+            return c
         if 'clang' in out:
             linker = None
             defines = _get_clang_compiler_defines(compiler, lang)