diff --git a/drivers/dahdi/xpp/xdefs.h b/drivers/dahdi/xpp/xdefs.h
index 054c30c..b15fa05 100644
--- a/drivers/dahdi/xpp/xdefs.h
+++ b/drivers/dahdi/xpp/xdefs.h
@@ -145,10 +145,12 @@ typedef char *charp;
 #endif
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 19)
-/* Also don't define this for later RHEL >= 5.2 . hex_asc is from the
- * same linux-2.6-net-infrastructure-updates-to-mac80211-iwl4965.patch
- * as is the bool typedef. */
-#if LINUX_VERSION_CODE != KERNEL_VERSION(2, 6, 18)  || !defined(hex_asc)
+/* Also don't define this for later RHEL >= 5.2. */
+#if defined(RHEL_RELEASE_CODE) && defined(RHEL_RELEASE_VERSION)
+#if RHEL_RELEASE_CODE < RHEL_RELEASE_VERSION(5, 3)
+typedef int bool;
+#endif
+#else
 typedef int bool;
 #endif
 #endif