diff --git a/sys/kms/gstkmsallocator.c b/sys/kms/gstkmsallocator.c
index 82af265cd8..2451e30592 100644
--- a/sys/kms/gstkmsallocator.c
+++ b/sys/kms/gstkmsallocator.c
@@ -30,6 +30,7 @@
 #include <drm.h>
 #include <xf86drm.h>
 #include <xf86drmMode.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
 #include <unistd.h>