This pullrequest removes redundant codepaths in
xbps-src-do{build,configure,install}.sh and joins the code in the
run_step function. This causes slightly different behavior to
do_install:
Do install will chdir to wrksrc only _before_ the first step. The
current behavior is that pre_install will run without a chdir, do_ and
post_ is runned with a chdir. This is a subtle but breaking change and
may cause some templates to break at install phase.
ba84655a13