build-liteipc.sh uses shell-specific functions not available in standard sh

[Wazubaba]

pushd and popd are shell-specific functions not available to standard sh itself, so possible solutions are to either require bash specifically in the shebang line or the better but sadly less elegant, replace them with cd calls to make it work in just about any shell. Otherwise it will require edits on any distro that doesn't switch sh to another shell, which still seems to be relatively common, unfortunately.

[liquidev]

Fixed in caa44d3.