diff --git a/src/common/String.h b/src/common/String.h
index bf4550824..a709e83c5 100644
--- a/src/common/String.h
+++ b/src/common/String.h
@@ -5,6 +5,7 @@
 #include <vector>
 #include <string>
 #include <limits>
+#include <locale>
 #include <ios>
 
 /*