XBPS_CACHEDIR has been replaced by XBPS_HOSTDIR in configuration file,
and this expects the following structure:
/host
|_ /build (previously /pkg-builddir)
|_ /binpkgs (previously /pkg-binpkgs)
|_ /repocache (previously /cachedir)
|_ /sources (previously /pkg-srcdistdir)
Thanks to str1ngs for the great idea!