xbps-bin: add a simple unpack cb that mimics the 'check' target.
xbps-bin: add a simple unpack cb that mimics the 'check' target.

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