diff --git a/helpers.c b/helpers.c
index 7a146c3..f6eae46 100644
--- a/helpers.c
+++ b/helpers.c
@@ -92,7 +92,7 @@
 #endif
 
 /* There is no strnlen in DJGPP */
-#if defined(__DJGPP__)
+#if defined(__DJGPP__) || !defined(HAVE_STRNLEN)
 size_t strnlen(const char *str, size_t n)
 {
 	size_t i;