diff --git a/lib/hostthre.c b/lib/hostthre.c
index 7ad521abd4b4afeb01384f037d8d99db045ff7de..32d212f14857e2f3745b479f4310c0970f149d7a 100644
--- a/lib/hostthre.c
+++ b/lib/hostthre.c
@@ -78,6 +78,7 @@
 #include "share.h"
 #include "strerror.h"
 #include "url.h"
+#include "multiif.h"
 
 #define _MPRINTF_REPLACE /* use our functions only */
 #include <curl/mprintf.h>