diff --git a/driver/ldmd.cpp b/driver/ldmd.cpp
index bd319c3d..fd7a537b 100644
--- a/driver/ldmd.cpp
+++ b/driver/ldmd.cpp
@@ -44,6 +44,7 @@
 
 #include <cassert>
 #include <cerrno>
+#include <cstdarg>
 #include <cstdio>
 #include <cstdlib>
 #include <numeric>