diff --git a/include/ifm.h b/include/ifm.h
index 700ca8c69..11366d6b5 100644
--- a/include/ifm.h
+++ b/include/ifm.h
@@ -25,7 +25,7 @@ typedef struct {
     unsigned char blue;
 } RGBDATA;
 
-#if __GNUC__ < 7
+#if __GNUC__ < 7 && !defined(bool)
   #ifndef __bool_var
   #define __bool_var
   typedef int bool;