posix: give the cached symlink a real target
The NamedTemporaryFile file is cleared up so checklink ends up as a dangling
symlink, causing cp -r in tests to complain on both Solaris and OS X. Use
a permanent file instead when there is a .hg/cache directory.
@echo off
rem launch hg.exe from parent folder
"%~dp0\..\hg.exe" %*