[gtk/f16c.msvc: 32/61] Work around compiler shortcomings on macOS

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

commit f6a33a927c697a3dedaa86f79dc66aab2e0b6b30
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Apr 7 22:38:47 2021 -0400

    Work around compiler shortcomings on macOS
    
    alias attributes don't work on Darwin, so
    do without.

 gsk/ngl/fp16.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
---
diff --git a/gsk/ngl/fp16.c b/gsk/ngl/fp16.c
index 22453ae210..e9a8c8fbce 100644
--- a/gsk/ngl/fp16.c
+++ b/gsk/ngl/fp16.c
@@ -123,7 +123,28 @@ resolve_half_to_float4 (void)
 
 #else
 
+#ifdef __APPLE__
+// turns out aliases don't work on Darwin
+
+void
+float_to_half4 (const float f[4],
+                guint16     h[4])
+{
+  float_to_half4_c (f, h);
+}
+
+void
+half_to_float4 (const guint16 h[4],
+                float         f[4])
+{
+  half_to_float4_c (h, f);
+}
+
+#else
+
 void float_to_half4 (const float f[4], guint16 h[4]) __attribute__((alias ("float_to_half4_c")));
 void half_to_float4 (const guint16 h[4], float f[4]) __attribute__((alias ("half_to_float4_c")));
 
+#endif
+
 #endif  /* GTK_HAS_F16C */