diff --git a/libexec/rtld-elf/rtld_lock.c b/libexec/rtld-elf/rtld_lock.c
index bf4caf71176b..23e623203e8e 100644
--- a/libexec/rtld-elf/rtld_lock.c
+++ b/libexec/rtld-elf/rtld_lock.c
@@ -42,6 +42,8 @@
  * using assembly language sequences in "rtld_start.S".
  */
 
+#include <machine/param.h>
+
 #include <signal.h>
 #include <stdlib.h>
 #include <time.h>