diff --git a/src/cryptlib/misc.h b/src/cryptlib/misc.h
index 664d993..d390fa2 100644
--- a/src/cryptlib/misc.h
+++ b/src/cryptlib/misc.h
@@ -9,7 +9,8 @@
  #include <string.h>
 #endif
 
-#if IS_MINT || IS_DOS_DJGPP // has memory.h, but memset defined in string.h anyway.
+#if defined(__MINT__) || defined(__DJGPP__)
+ // OS has memory.h, but memset defined in string.h anyway.
  #include <string.h>
 #endif