mesa: don't include math.h in compiler.h

Not needed by anything in that header.  Include math.h or c99_math.h
where needed instead.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>

src/mesa/drivers/x11/xm_tri.c

@@ -30,6 +30,7 @@
  */
 
 
+#include "c99_math.h"
 #include "main/imports.h"
 #include "main/mtypes.h"
 #include "glxheader.h"