diff --git a/src/midout.cpp b/src/midout.cpp
index 2e6dd3f44fe74d3a275f7c4b5dbefd44f38d1211..d3042e4edddc14cac0ee1bd1f97a8a8d940dce8a 100644
--- a/src/midout.cpp
+++ b/src/midout.cpp
@@ -19,6 +19,7 @@ void midout_empty() {
 
 #include <sys/types.h>
 #include <unistd.h>
+#include <errno.h>
 
 namespace {
     class UsedTypes {