setup: copy pythonXY.dll next to the hg.exe wrapper when building This avoids the problem of having the newly built binary complaining that it can't find the DLL. There is an option in the python.org installer to add the python install to PATH (which defaulted to "on" with py2, and therefore was not an issue up to this point), but that makes switching between python versions harder. This shouldn't be an issue with the PyOxidizer binary, but that current has issues running some of the tests, and took noticeably longer to build last time I tried it. Differential Revision: https://phab.mercurial-scm.org/D9362