Introduce prototype-style function definition for wcscpy on 32-bit
POWER.  The old-style function definition was removed upstream in:

commit 93be09e7259caf227dd586404f3c74b61c830cb4
Author: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
Date:   Mon Oct 14 09:43:31 2013 -0500

    PowerPC: multiarch wcscpy for PowerPC32

diff --git a/sysdeps/powerpc/powerpc32/power6/wcscpy.c b/sysdeps/powerpc/powerpc32/power6/wcscpy.c
index 9bd907788e6f2337..0af09793f7ce43e0 100644
--- a/sysdeps/powerpc/powerpc32/power6/wcscpy.c
+++ b/sysdeps/powerpc/powerpc32/power6/wcscpy.c
@@ -22,9 +22,7 @@
 
 /* Copy SRC to DEST.  */
 wchar_t *
-wcscpy (dest, src)
-     wchar_t *dest;
-     const wchar_t *src;
+wcscpy (wchar_t *dest, const wchar_t *src)
 {
   wint_t c,d;
   wchar_t *wcp, *wcp2;