bug#14513: 24.3.50; Site load-path pieces differ in MSYS build

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 4 Jun 2013 19:27:50 +0100
> From: Richard Copley <rcopley@gmail.com>
> 
> One last time I'll advocate the change I was thinking of initially: re-add
> the "ROOT/../site-lisp" entry to PATH_SITELOADSEARCH in epaths.nt, as in
> the attached patch.

I hear you, but please understand: it's not just addition of a
directory to the variable.  These directories are tested for existence
at startup, and Emacs displays a warning of any of them doesn't exist.
So, if the Windows build had a directory that other builds don't, we
would need Windows-specific code to ignore this specific directory if
it doesn't exist, or make sure it is created -- only on Windows -- at
"make install" time.  And since this list of directories is
constructed in a very convoluted way, paying attention to
EMACSLOADPATH in the environment and to whether Emacs is run
uninstalled, it is not easy to identify that single directory and
ignore it.

All this flies in the face of the main reason why I made the MSYS
build happen: remove as much Windows specific issues, code, and
configury, so that other developers and maintainers could understand
how the Windows port is built, and could make changes without fear
they break the Windows port too easily.  If we don't stick to this
attitude, the Windows port is in real danger of falling by the wayside
at the slightest change of fortunes.