The RUNTIME_PREFIX feature comes from Git for Windows, but it was
enhanced to allow support for other platforms. While changing the
original idea, the concept was also improved by not forcing argv[0] to
be adjusted.
Let's allow the same for Windows by implementing a helper just as for
the other platforms.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>