diff --git a/cpukit/libcsupport/src/ctermid.c b/cpukit/libcsupport/src/ctermid.c
index 8df70e1263..bb47f9c350 100644
--- a/cpukit/libcsupport/src/ctermid.c
+++ b/cpukit/libcsupport/src/ctermid.c
@@ -23,6 +23,7 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <sys/unistd.h>
 
 static char *ctermid_name = "/dev/console";