merge with stable

setup: fix mac build broken by e42d18538e1d Sometimes xcodebuild prints warnings to stderr, but runcmd() assumes anything printed to stderr implies failure. Since runcmd() was originally only intended to run hg, this was fine until it was pressed into service for running xcodebuild. Thus: split runcmd() into two parts: runcmd(), which does the minimal amount of work to run a subprocess, and runhg(), which calls runcmd().

color: don't mention internal function in docstring The render_text function actually never existed, the docstring probably meant the render_effects function instead.