--- links-2.15/links.h	2018-03-11 14:36:26.000000000 +0100
+++ links-2.15/links.h.new	2018-04-30 11:38:00.489158338 +0200
@@ -53,6 +53,7 @@
 #include <stdarg.h>
 #include <stddef.h>
 #ifdef HAVE_UNISTD_H
+#define _GNU_SOURCE 1 /* so that <unistd.h> defines get_current_dir_name() */
 #include <unistd.h>
 #endif
 #ifdef HAVE_STRING_H