diff --git a/src/tweetnacl.c b/src/tweetnacl.c
index 81560844..0520131b 100644
--- a/src/tweetnacl.c
+++ b/src/tweetnacl.c
@@ -31,8 +31,8 @@
 #if defined (ZMQ_USE_TWEETNACL)
 
 //  Disable warnings for this source only, rather than for the whole
-//  codebase
-#ifdef __GNUC__
+//  codebase when building with C99 or with Microsoft's compiler
+#if defined __GNUC__ && __STDC_VERSION__ < 201112L
 #   pragma GCC diagnostic ignored "-Wsign-compare"
 #elif defined _MSC_VER
 #   pragma warning (disable:4018 4244 4146)