WIP: bpo-29723: Set sys.path[0] correctly for importer-as-main#571

ncoghlan wants to merge 3 commits intopython:3.6python/cpython:3.6from

ncoghlan:bpo-29723-sys-path-configuration-errorncoghlan/cpython:bpo-29723-sys-path-configuration-errorCopy head branch name to clipboard