diff --git a/include/features.h b/include/features.h
index 3cc3e579..f4d651ef 100644
--- a/include/features.h
+++ b/include/features.h
@@ -24,6 +24,8 @@
 
 #if __STDC_VERSION__ >= 199901L || defined(__cplusplus)
 #define __inline inline
+#elif !defined(__GNUC__)
+#define __inline
 #endif
 
 #if __STDC_VERSION__ >= 201112L