diff --git a/cpukit/libfs/src/rfs/rtems-rfs-rtems.c b/cpukit/libfs/src/rfs/rtems-rfs-rtems.c
index 4e3370b04a..100f70c538 100644
--- a/cpukit/libfs/src/rfs/rtems-rfs-rtems.c
+++ b/cpukit/libfs/src/rfs/rtems-rfs-rtems.c
@@ -20,6 +20,7 @@
 #include "config.h"
 #endif
 
+#include <sys/param.h>
 #include <inttypes.h>
 #include <string.h>
 #include <stdlib.h>