diff --git a/src/unix/darwin-proctitle.c b/src/unix/darwin-proctitle.c
index b7267caa..cbb7ea42 100644
--- a/src/unix/darwin-proctitle.c
+++ b/src/unix/darwin-proctitle.c
@@ -21,6 +21,7 @@
 #include <dlfcn.h>
 #include <errno.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include <TargetConditionals.h>