diff --git a/runalarm.c b/runalarm.c
index fb8617a..95a40ac 100644
--- a/runalarm.c
+++ b/runalarm.c
@@ -17,6 +17,7 @@ limitations under the License.
 #define _GNU_SOURCE /* basename */
 
 #include <errno.h>
+#include <libgen.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/runlock.c b/runlock.c
index 0e446b0..75ac08f 100644
--- a/runlock.c
+++ b/runlock.c
@@ -18,6 +18,7 @@ limitations under the License.
 
 #include <errno.h>
 #include <fcntl.h>
+#include <libgen.h>
 #include <limits.h>
 #include <signal.h>
 #include <stdio.h>