st/egl: Fix a void pointer arithmetic warning.

diff --git a/src/gallium/state_trackers/egl/x11/native_dri2.c b/src/gallium/state_trackers/egl/x11/native_dri2.c
index adcc3b3..c82e2da 100644 (file)
--- a/src/gallium/state_trackers/egl/x11/native_dri2.c
+++ b/src/gallium/state_trackers/egl/x11/native_dri2.c
@@ -799,7 +799,7 @@ dri2_display_hash_table_hash(void *key)
 static int
 dri2_display_hash_table_compare(void *key1, void *key2)
 {
-   return (key1 - key2);
+   return ((char *) key1 - (char *) key2);
 }
 
 struct native_display *