gallium: fix warnings

src/gallium/winsys/xlib/xm_winsys.c

 }
 
 
-struct pipe_winsys *
+static struct pipe_winsys *
 xmesa_get_pipe_winsys(struct xmesa_visual *xm_vis)
 {
    static struct xmesa_pipe_winsys *ws = NULL;

src/mesa/state_tracker/st_atom_sampler.c

   */
  
 
+#include "main/macros.h"
+
 #include "st_context.h"
 #include "st_atom.h"
 #include "st_program.h"
 #include "pipe/p_context.h"
 #include "pipe/p_defines.h"
-#include "pipe/p_util.h"
+
 #include "cso_cache/cso_context.h"