portableproplib: fix gzFile to make it work with zlib-1.2.6.
portableproplib: fix gzFile to make it work with zlib-1.2.6.

datenwolf/xbps,stpx/xbps,ebfe/xbps,ebfe/xbps,ebfe/xbps,datenwolf/xbps,stpx/xbps,datenwolf/xbps,stpx/xbps