https://bugs.gentoo.org/902995

--- a/src/work_pool.c
+++ b/src/work_pool.c
@@ -39,6 +39,7 @@
 
 #include "config.h"
 
+#include <assert.h>
 #include <sys/types.h>
 #if !defined(_WIN32)
 #include <netinet/in.h>