https://bugs.gentoo.org/870763

--- a2ps-4.14/lib/path-concat.c
+++ a2ps-4.14/lib/path-concat.c
@@ -26,6 +26,7 @@
 #endif
 
 #include <stdio.h>
+#include <stdlib.h>
 #if HAVE_STRING_H
 # include <string.h>
 #endif