diff --git a/crypto/o_str.c b/crypto/o_str.c
index 174db3156e..efe20b77a9 100644
--- a/crypto/o_str.c
+++ b/crypto/o_str.c
@@ -56,7 +56,8 @@
  *
  */
 
-#include <o_str.h>
+#include <strings.h>
+#include "o_str.h"
 #include <openssl/e_os2.h>
 
 int OPENSSL_strncasecmp(const char *str1, const char *str2, size_t n)