diff --git a/lib/mini-gmp.c b/lib/mini-gmp.c
index 8577b59ef6d..14cabd12311 100644
--- a/lib/mini-gmp.c
+++ b/lib/mini-gmp.c
@@ -90,6 +90,7 @@ see https://www.gnu.org/licenses/.  */
 #define gmp_assert_nocarry(x) do { \
     mp_limb_t __cy = (x);	   \
     assert (__cy == 0);		   \
+    (void) (__cy);		   \
   } while (0)
 
 #define gmp_clz(count, x) do {						\
diff --git a/lib/verify.h b/lib/verify.h
index 07b2f4866f2..c2d2a566706 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -34,7 +34,7 @@
 #ifndef __cplusplus
 # if (201112L <= __STDC_VERSION__ \
       || (!defined __STRICT_ANSI__ \
-          && (4 < __GNUC__ + (6 <= __GNUC_MINOR__) || 4 <= __clang_major__)))
+          && (4 < __GNUC__ + (6 <= __GNUC_MINOR__) || 5 <= __clang_major__)))
 #  define _GL_HAVE__STATIC_ASSERT 1
 # endif
 # if (202000L <= __STDC_VERSION__ \