linkers: make sure the linker is actually Apple when matching failure

Not all "use -v" errors are Apple ld, and if it doesn't have better
output with -v instead of --version, we should not assume that is what
it is.

mesonbuild/linkers/detect.py

@@ -186,18 +186,24 @@ def guess_nix_linker(env: 'Environment', compiler: T.List[str], comp_class: T.Ty
             v = search_version(o)
 
         linker = LLVMDynamicLinker(compiler, for_machine, comp_class.LINKER_PREFIX, override, version=v)
-    # first is for apple clang, second is for real gcc, the third is icc
+    # first might be apple clang, second is for real gcc, the third is icc
     elif e.endswith('(use -v to see invocation)\n') or 'macosx_version' in e or 'ld: unknown option:' in e:
         if isinstance(comp_class.LINKER_PREFIX, str):
-            _, _, e = Popen_safe(compiler + [comp_class.LINKER_PREFIX + '-v'] + extra_args)
+            cmd = compiler + [comp_class.LINKER_PREFIX + '-v'] + extra_args
         else:
-            _, _, e = Popen_safe(compiler + comp_class.LINKER_PREFIX + ['-v'] + extra_args)
-        for line in e.split('\n'):
+            cmd = compiler + comp_class.LINKER_PREFIX + ['-v'] + extra_args
+        mlog.debug('-----')
+        mlog.debug(f'Detecting Apple linker via: {join_args(cmd)}')
+        _, newo, newerr = Popen_safe(cmd)
+        mlog.debug(f'linker stdout:\n{newo}')
+        mlog.debug(f'linker stderr:\n{newerr}')
+
+        for line in newerr.split('\n'):
             if 'PROJECT:ld' in line:
                 v = line.split('-')[1]
                 break
         else:
-            v = 'unknown version'
+            __failed_to_detect_linker(compiler, check_args, o, e)
         linker = AppleDynamicLinker(compiler, for_machine, comp_class.LINKER_PREFIX, override, version=v)
     elif 'GNU' in o or 'GNU' in e:
         cls: T.Type[GnuDynamicLinker]