diff --git a/last.c b/last.c
index 5aeeb8f..7308a42 100644
--- a/last.c
+++ b/last.c
@@ -1,5 +1,6 @@
 /* See LICENSE file for copyright and license details. */
 #include <errno.h>
+#include <libgen.h>
 #include <paths.h>
 #include <pwd.h>
 #include <stdio.h>
diff --git a/ps.c b/ps.c
index aedf7c4..c0e53f1 100644
--- a/ps.c
+++ b/ps.c
@@ -3,6 +3,7 @@
 #include <sys/sysinfo.h>
 
 #include <errno.h>
+#include <libgen.h>
 #include <limits.h>
 #include <pwd.h>
 #include <stdio.h>