Pullup ticket #4540 - requested by tron
net/libtorrent: build fix

Revisions pulled up:
- net/libtorrent/Makefile                                      1.53

-------------------------------------------------------------------
  Module Name: pkgsrc
  Committed By: tron
  Date: Tue Nov  4 08:36:17 UTC 2014

  Modified Files:
  pkgsrc/net/libtorrent: Makefile

  Log Message:
  Attempt to fix build problems of "rtorretn" on 32bit platforms like
  Linux/i586 or NetBSD/i386.

  To generate a diff of this commit:
  cvs rdiff -u -r1.52 -r1.53 pkgsrc/net/libtorrent/Makefile

(spz)