diff --git a/lib/http_ntlm.c b/lib/http_ntlm.c
index 29615a470e2af9dce1d1706f0f6f8309b5faf5ee..bb17f371b37f10077799c734bdc194762c9619e9 100644
--- a/lib/http_ntlm.c
+++ b/lib/http_ntlm.c
@@ -46,6 +46,7 @@
 #include "base64.h"
 #include "http_ntlm.h"
 #include "url.h"
+#include "http.h" /* for Curl_http_auth_stage() */
 
 #define _MPRINTF_REPLACE /* use our functions only */
 #include <curl/mprintf.h>