fix zlib autodetection error introduced in [3360]. Fixes #517
fix zlib autodetection error introduced in [3360]. Fixes #517

hamedramzi/libtorrent,TeoTwawki/libtorrent,snowyu/libtorrent,snowyu/libtorrent,snowyu/libtorrent,TeoTwawki/libtorrent,hamedramzi/libtorrent,TeoTwawki/libtorrent,snowyu/libtorrent,hamedramzi/libtorrent,TeoTwawki/libtorrent,hamedramzi/libtorrent,snowyu/libtorrent,TeoTwawki/libtorrent,hamedramzi/libtorrent,hamedramzi/libtorrent,snowyu/libtorrent,TeoTwawki/libtorrent