Introduce prototypes for scandir, scandirat.  This was implemented
upstream in:

commit d2ee815ad677bba720c4f0275c1d6065f5809e7a
Author: Roland McGrath <roland@hack.frob.com>
Date:   Wed May 13 12:34:11 2015 -0700

    Refactor scandir/scandirat to use common tail.

Not backported here because of its dependency on the fix for
swbz#17999.

diff --git a/dirent/scandir.c b/dirent/scandir.c
index 6dce54d64a3effa2..39c4c20e2b22804d 100644
--- a/dirent/scandir.c
+++ b/dirent/scandir.c
@@ -34,11 +34,9 @@
 
 
 int
-SCANDIR (dir, namelist, select, cmp)
-     const char *dir;
-     DIRENT_TYPE ***namelist;
-     int (*select) (const DIRENT_TYPE *);
-     int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **);
+SCANDIR (const char *dir, DIRENT_TYPE ***namelist,
+         int (*select) (const DIRENT_TYPE *),
+         int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **))
 {
   return SCANDIRAT (AT_FDCWD, dir, namelist, select, cmp);
 }
diff --git a/dirent/scandirat.c b/dirent/scandirat.c
index c2704baa88ef71d0..0200171a64139933 100644
--- a/dirent/scandirat.c
+++ b/dirent/scandirat.c
@@ -52,12 +52,9 @@ __scandir_cancel_handler (void *arg)
 
 
 int
-SCANDIRAT (dfd, dir, namelist, select, cmp)
-     int dfd;
-     const char *dir;
-     DIRENT_TYPE ***namelist;
-     int (*select) (const DIRENT_TYPE *);
-     int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **);
+SCANDIRAT (int dfd, const char *dir, DIRENT_TYPE ***namelist,
+	   int (*select) (const DIRENT_TYPE *),
+	   int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **))
 {
   DIR *dp = __opendirat (dfd, dir);
   DIRENT_TYPE **v = NULL;