Check gcc version

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/gcm.c b/library/gcm.c
index 976d6d7..5dfac23 100644
--- a/library/gcm.c
+++ b/library/gcm.c
@@ -412,14 +412,14 @@
         while (iv_len > 0) {
             use_len = (iv_len < 16) ? iv_len : 16;
 
-#if defined(MBEDTLS_COMPILER_IS_GCC)
+#if defined(MBEDTLS_COMPILER_IS_GCC) && (MBEDTLS_GCC_VERSION >= 70110)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic warning "-Wstringop-overflow=0"
 #endif
 
             mbedtls_xor(ctx->y, ctx->y, p, use_len);
 
-#if defined(MBEDTLS_COMPILER_IS_GCC)
+#if defined(MBEDTLS_COMPILER_IS_GCC) && (MBEDTLS_GCC_VERSION >= 70110)
 #pragma GCC diagnostic pop
 #endif