diff --git a/lib/base64.c b/lib/base64.c
index 2a49b5acd6..919eb62359 100644
--- a/lib/base64.c
+++ b/lib/base64.c
@@ -31,6 +31,7 @@
   !defined(CURL_DISABLE_SMTP) || \
   !defined(CURL_DISABLE_POP3) || \
   !defined(CURL_DISABLE_IMAP) || \
+  !defined(CURL_DISABLE_DIGEST_AUTH) || \
   !defined(CURL_DISABLE_DOH) || defined(USE_SSL) || defined(BUILDING_CURL)
 #include "curl/curl.h"
 #include "warnless.h"