porting: OSX/Darwin 10.9 porting issues

xdrproc_t() arguments are variadic and non-variadic

On OSX > 10.9
-------------
typedef bool_t (*xdrproc_t)(XDR *, void *, unsigned int);

On OSX < 10.9
------------
typedef bool_t (*xdrproc_t)(XDR *, ...);

FreeBSD all versions
------------
typedef bool_t (*xdrproc_t)(XDR *, ...);

NetBSD 6.1.4
-----------
typedef bool_t (*xdrproc_t)(XDR *, const void *);

Linux all versions
-----------
typedef bool_t (*xdrproc_t)(XDR *, void *,...);

This weird and odd implementations across various platforms
should be handled properly.

Change-Id: Iad8b7da2e5b82526bf3708cff31ab10ce09f59c9
BUG: 1128820
Signed-off-by: Harshavardhana <harsha@harshavardhana.net>
Reviewed-on: http://review.gluster.org/8458
Reviewed-by: Emmanuel Dreyfus <manu@netbsd.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>