Fix musl build

Downloaded from
http://git.alpinelinux.org/cgit/aports/plain/main/mesa/musl-fixes.patch

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>

--- ./src/gallium/winsys/svga/drm/vmw_screen.h.orig
+++ ./src/gallium/winsys/svga/drm/vmw_screen.h
@@ -34,7 +34,7 @@
 #ifndef VMW_SCREEN_H_
 #define VMW_SCREEN_H_
 
-
+#include <sys/stat.h>
 #include "pipe/p_compiler.h"
 #include "pipe/p_state.h"