diff --git a/src/emu/diimage.cpp b/src/emu/diimage.cpp
index 016f577f071..c741cab8b40 100644
--- a/src/emu/diimage.cpp
+++ b/src/emu/diimage.cpp
@@ -24,6 +24,7 @@
 #include "zippath.h"
 
 #include <algorithm>
+#include <cstdarg>
 #include <cstring>
 #include <regex>
 #include <sstream>