Use gmtime_s() for IAR
diff --git a/library/platform_util.c b/library/platform_util.c
index 68d2522..e440e5a 100644
--- a/library/platform_util.c
+++ b/library/platform_util.c
@@ -88,6 +88,8 @@
 {
 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
     return( ( gmtime_s( tm_buf, tt ) == 0 ) ? tm_buf : NULL );
+#elif defined(__IAR_SYSTEMS_ICC__)
+    return( gmtime_s( tt, tm_buf ) );
 #elif !defined(PLATFORM_UTIL_USE_GMTIME)
     return( gmtime_r( tt, tm_buf ) );
 #else