diff --git a/builder/yajl-c.c b/builder/yajl-c.c
index 67de09318..6b7594372 100644
--- a/builder/yajl-c.c
+++ b/builder/yajl-c.c
@@ -31,7 +31,9 @@
 /* GCC can't work out that the YAJL_IS_<foo> test is sufficient to
  * ensure that YAJL_GET_<foo> later doesn't return NULL.
  */
+#if defined(__GNUC__) && __GNUC__ >= 6 /* gcc >= 6 */
 #pragma GCC diagnostic ignored "-Wnull-dereference"
+#endif
 
 #define Val_none (Val_int (0))
 
diff --git a/daemon/debug.c b/daemon/debug.c
index 864812079..da4cfc8be 100644
--- a/daemon/debug.c
+++ b/daemon/debug.c
@@ -990,7 +990,9 @@ do_internal_rhbz914931 (int count)
 }
 
 #pragma GCC diagnostic push
+#if defined(__GNUC__) && GUESTFS_GCC_VERSION >= 60000 /* gcc >= 6 */
 #pragma GCC diagnostic ignored "-Wnull-dereference"
+#endif
 
 static void
 deliberately_cause_a_segfault (void)
diff --git a/daemon/ldm.c b/daemon/ldm.c
index 25ca95206..8ad2fb33b 100644
--- a/daemon/ldm.c
+++ b/daemon/ldm.c
@@ -35,7 +35,9 @@
 /* GCC can't work out that the YAJL_IS_<foo> test is sufficient to
  * ensure that YAJL_GET_<foo> later doesn't return NULL.
  */
+#if defined(__GNUC__) && GUESTFS_GCC_VERSION >= 60000 /* gcc >= 6 */
 #pragma GCC diagnostic ignored "-Wnull-dereference"
+#endif
 
 GUESTFSD_EXT_CMD(str_ldmtool, ldmtool);
 
diff --git a/p2v/gui.c b/p2v/gui.c
index e5f026f5d..58310bf05 100644
--- a/p2v/gui.c
+++ b/p2v/gui.c
@@ -69,7 +69,9 @@
 /* errors in <gtk.h> */
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wstrict-prototypes"
+#if defined(__GNUC__) && __GNUC__ >= 6 /* gcc >= 6 */
 #pragma GCC diagnostic ignored "-Wshift-overflow"
+#endif
 #include <gtk/gtk.h>
 #pragma GCC diagnostic pop
 
diff --git a/p2v/main.c b/p2v/main.c
index adbee9fae..36cf16fa1 100644
--- a/p2v/main.c
+++ b/p2v/main.c
@@ -36,7 +36,9 @@
 /* errors in <gtk.h> */
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wstrict-prototypes"
+#if defined(__GNUC__) && __GNUC__ >= 6 /* gcc >= 6 */
 #pragma GCC diagnostic ignored "-Wshift-overflow"
+#endif
 #include <gtk/gtk.h>
 #pragma GCC diagnostic pop