Introduce prototype-style function definition for sem_unlink.  This

happened upstream as part of:

commit e4f639e4a106d90c6f3159230788653fd6e40a26

Author: Roland McGrath <roland@hack.frob.com>

Date:   Fri Dec 12 13:17:21 2014 -0800

    NPTL: Refactor named semaphore code to use shm-directory.h

diff --git a/nptl/sem_unlink.c b/nptl/sem_unlink.c

index 610d82e7a6fe5bd1..1523522c41a52d76 100644

--- a/nptl/sem_unlink.c

+++ b/nptl/sem_unlink.c

@@ -25,8 +25,7 @@

 int

-sem_unlink (name)

-     const char *name;

+sem_unlink (const char *name)

 {

   char *fname;

   size_t namelen;