diff --git a/include/stdc-predef.h b/include/stdc-predef.h
index f8cd4b89..af1a2799 100644
--- a/include/stdc-predef.h
+++ b/include/stdc-predef.h
@@ -7,4 +7,7 @@
 #define __STDC_IEC_559__ 1
 #endif
 
+#define __STDC_UTF_16__ 1
+#define __STDC_UTF_32__ 1
+
 #endif