osutil: write a C implementation of statfiles for unix
This makes a big difference to performance.
In a clean working directory containing 170,000 files, performance of
"hg --time diff" improves from 2.38 seconds to 1.69.
from mercurial.hg import parseurl
def testparse(url, branch=[]):
print '%s, branches: %r' % parseurl(url, branch)
testparse('http://example.com/no/anchor')
testparse('http://example.com/an/anchor#foo')
testparse('http://example.com/no/anchor/branches', branch=['foo'])
testparse('http://example.com/an/anchor/branches#bar', branch=['foo'])
testparse('http://example.com/an/anchor/branches-None#foo', branch=None)
testparse('http://example.com/')
testparse('http://example.com')
testparse('http://example.com#foo')