On POSIX platforms, the 'add', 'addremove', 'copy' and 'rename' commands now
warn if a file has a name that can't be checked out on Windows.
Example:
$ hg add con.xml
warning: filename contains 'con', which is reserved on Windows: 'con.xml'
$ hg status
A con.xml
The file is added despite the warning.
The warning is ON by default. It can be suppressed by setting the config option
'portablefilenames' in section 'ui' to 'ignore' or 'false':
$ hg --config ui.portablefilenames=ignore add con.xml
$ hg sta
A con.xml
If ui.portablefilenames is set to 'abort', then the command is aborted:
$ hg --config ui.portablefilenames=abort add con.xml
abort: filename contains 'con', which is reserved on Windows: 'con.xml'
On Windows, the ui.portablefilenames config setting is irrelevant and the
command is always aborted if a problematic filename is found.
