[gtk/f16c.msvc: 5/6] meson.build: Improve F16C detection on Visual Studio

[Chun-wei Fan <fanchunwei src gnome org>]

commit ce1ceac8aa8878b479b29e59063cbafff8f34070
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Mon Apr 12 16:24:37 2021 +0800

    meson.build: Improve F16C detection on Visual Studio
    
    The __builtin_cpu...() intrisics are strictly for GCC/CLang-based compilers, so
    don't use them in the checking code on Visual Studio.  The test code will still
    compile without this change, but will certainly fail if we want it to link.

 meson.build | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/meson.build b/meson.build
index 641208158c..902bd72031 100644
--- a/meson.build
+++ b/meson.build
@@ -707,8 +707,10 @@ int main () {
   __m128i i = _mm_cvtps_ph (s, 0);
   _mm_storel_epi64 ((__m128i*)h, i);
 
+#if defined (__GNUC__) || defined (__clang__)
   __builtin_cpu_init ();
   __builtin_cpu_supports ("f16c");
+#endif
 
     return 0;
 }'''