diff --git a/options.cpp b/options.cpp
index 4e77bf0d..b2d81f3a 100644
--- a/options.cpp
+++ b/options.cpp
@@ -23,6 +23,7 @@
 #include "config.h"
 
 #include "debug.hpp"
+#include "string.hpp"
 #include "types.hpp"
 #include "types/casts.hpp"