build: Check for sincosf()

sincosf() is really a GCC-specific function that may more may not be
supported on non-GCC compilers, so we want to check for it, otherwise we
use a fallback implementation, not unlike the one in
demos/gtk-demo/gtkgears.c.

gsk/gsktransform.c

@@ -712,7 +712,15 @@ _sincos (float  deg,
     }
   else
     {
-      sincosf (deg * M_PI / 180.0, out_s, out_c);
+      float angle = deg * M_PI / 180.0;
+
+#ifdef HAVE_SINCOSF
+      sincosf (angle, out_s, out_c);
+#else
+      *out_s = sinf (angle);
+      *out_c = cosf (angle);
+#endif
+
     }
 }
 

meson.build

@@ -198,6 +198,7 @@ check_functions = [
   'log2',
   'exp2',
   'sincos',
+  'sincosf',
 ]
 
 foreach func : check_functions