diff --git a/base/i2-base.h b/base/i2-base.h
index 36d2cdefe..a2c978548 100644
--- a/base/i2-base.h
+++ b/base/i2-base.h
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
+#include <errno.h>
 
 #include <memory>
 #include <string>