meson: Fix Clang microsoft-enum-value detection.

Fixes: 3aee4627

 ("meson: add windows compiler checks and libraries")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Part-of: <mesa/mesa!7543>

meson.build

@@ -1030,10 +1030,6 @@ if cc.get_id() == 'msvc'
       cpp_args += a
     endif
   endforeach
-  if cc.has_argument('-Wmicrosoft-enum-value')  # Clang
-    c_args += '-Wno-microsoft-enum-value'
-    cpp_args += '-Wno-microsoft-enum-value'
-  endif
 else
   _trial = [
     '-Werror=implicit-function-declaration',
@@ -1102,6 +1098,11 @@ else
       cpp_msvc_compat_args += a
     endif
   endforeach
+
+  if cc.has_argument('-Wmicrosoft-enum-value')  # Clang
+    c_args += '-Wno-microsoft-enum-value'
+    cpp_args += '-Wno-microsoft-enum-value'
+  endif
 endif
 
 # set linker arguments