diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index d3b46a2ca0..81a776e4fd 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -15,6 +15,7 @@
 
 #include <time.h>
 #include <sys/time.h>
+#include <sys/wait.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>