Fix builds with compilers other than gcc 3.0 & newer

Add #include "glheader.h" for definition of __builtin_expect for compilers
that don't support it.

Signed-off-by: Brian Paul <brian.paul@tungstengraphics.com>

src/glx/x11/indirect_vertex_program.c

@@ -23,6 +23,7 @@
  * SOFTWARE.
  */
 
+#include "glheader.h"
 #include <inttypes.h>
 #include <GL/gl.h>
 #include "indirect.h"

src/glx/x11/pixelstore.c

@@ -34,6 +34,7 @@
 **
 */
 
+#include "glheader.h"
 #include "glxclient.h"
 #include "indirect.h"
 

src/glx/x11/singlepix.c

@@ -34,6 +34,7 @@
 **
 */
 
+#include "glheader.h"
 #include "packsingle.h"
 #include "indirect.h"
 #include "dispatch.h"