MidnightBSD may also not have strnlen
diff --git a/src/strnlen.h b/src/strnlen.h
index 007da2e..fdd7fe3 100644
--- a/src/strnlen.h
+++ b/src/strnlen.h
@@ -7,7 +7,7 @@
#ifndef INCLUDE_strlen_h__
#define INCLUDE_strlen_h__
-#if defined(__MINGW32__) || defined(__sun) || defined(__APPLE__)
+#if defined(__MINGW32__) || defined(__sun) || defined(__APPLE__) || defined(__MidnightBSD__)
# define NO_STRNLEN
#endif