py3: handle sysstr conversion around get/set attr in contrib/perf

py3: proxy posixfile objects to re-add a useful 'name' attribute on Windows This file object is used in the vfs layer, so there are many errors like this: ... File "mercurial\localrepo.py", line 2569, in savecommitmessage return self.pathto(fp.name[len(self.root) + 1:]) TypeError: 'int' object is not subscriptable It looks like the 'name' value is actually the fileno() value, and the documentation says the name parameter to PyFile_FromFd() is ignored. [1] I tried just assigning the attribute after osutil.posixfile() returns, but that crashes saying that it's read-only. [1] https://docs.python.org/3.6/c-api/file.html

py3: don't use os.getcwdb() on Windows to avoid DeprecationWarnings See also ac32685011a3.