setup: avoid procedure related to hg.exe at setup.py --pure Before this patch, "setup.py --pure" fails on Windows, because hgbuildscripts.run() tries to copy "hg.exe", which doesn't generated at "setup.py --pure". At that time, run_command('build_hgexe') invoked in hgbuildscripts.run() does nothing and returns successfully. Therefore, subsequent procedure assuming existence of "hg.exe" fails. This patch avoids procedure related to "hg.exe" (= all of hgbuildscripts.run() except for build_scripts.run() invocation) at "setup.py --pure".