gl.h: remove stale comment, trailing whitespace

Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

include/GL/gl.h

@@ -47,7 +47,7 @@
 #    define GLAPI __declspec(dllimport)
 #  else /* for use with static link lib build of Win32 edition only */
 #    define GLAPI extern
-#  endif /* _STATIC_MESA support */
+#  endif
 #  if defined(__MINGW32__) && defined(GL_NO_STDCALL) || defined(UNDER_CE)  /* The generated DLLs by MingW with STDCALL are not compatible with the ones done by Microsoft's compilers */
 #    define GLAPIENTRY
 #  else