diff --git a/jam/execunix.c b/jam/execunix.c
index 11f73ca1db..e19293ba27 100644
--- a/jam/execunix.c
+++ b/jam/execunix.c
@@ -56,6 +56,7 @@
 
 # ifdef unix
 # include <unistd.h>
+# include <sys/wait.h>
 
 # ifdef USE_POSIX_SPAWN
 extern char **environ;