Windows does not have strtok_r (and while it does have an identical
strtok_s, but it is not obvious how to use it). Grab an
implementation from glibc.
The svn-fe tool uses strtok_r to parse paths.
Acked-by: Johannes Sixt <j6t@kdbg.org>
Helped-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>