egl: Fix inclusion of egl.h+mesa_glinterop.h

Previously clang would warn about redefinition of typedef EGLDisplay. Avoid
this by adding preprocessor guards to mesa_glinterop.h and including it
after EGL.h is indirectly included.

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index ed79e0d..1259433 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -46,7 +46,6 @@
 #endif
 #include <GL/gl.h>
 #include <GL/internal/dri_interface.h>
-#include "GL/mesa_glinterop.h"
 #include <sys/types.h>
 #include <sys/stat.h>
 
@@ -61,6 +60,7 @@
 #endif
 
 #include "egl_dri2.h"
+#include "GL/mesa_glinterop.h"
 #include "loader/loader.h"
 #include "util/u_atomic.h"
 #include "util/u_vector.h"