diff --git a/src/libraries/libisc-new/src/isc_tcp.c b/src/libraries/libisc-new/src/isc_tcp.c
index 0750fc4e05398daaee36d2c19b80f66b6ed03015..c02d7ed11aea0451b3d9ecd501413116bd54c8c2 100644
--- a/src/libraries/libisc-new/src/isc_tcp.c
+++ b/src/libraries/libisc-new/src/isc_tcp.c
@@ -51,7 +51,6 @@ extern int listen(int, int);
 /*extern int bind(int, struct sockaddr *, int);*/
 extern int close(int);
 /*extern int atoi(const char *str);*/
-extern time_t sleep(time_t);
 /*extern int accept(int fd, struct sockaddr *sock, int *len);*/