diff --git a/lib/curl_multibyte.c b/lib/curl_multibyte.c
index e2078e05a..e78bb5002 100644
--- a/lib/curl_multibyte.c
+++ b/lib/curl_multibyte.c
@@ -22,6 +22,8 @@
 
 #include "curl_setup.h"
 
+#include <curl/curl.h>
+
 #if defined(USE_WIN32_IDN) || ((defined(USE_WINDOWS_SSPI) || \
                                 defined(USE_WIN32_LDAP)) && defined(UNICODE))