Bloat in Windows (revisited)

[Phillip Lord]

A while back, we had some discussion about the Emacs packages for
windows.

https://lists.gnu.org/archive/html/emacs-devel/2019-04/msg00719.html

I have now implemented the first part of this (no debug symbols in
release builds); at least hopefully, as it's hard to test for sure till
the first release of Emacs-27.

I have also been playing around with the problem of msys2 pulling in a
fairly wide set of dependencies. Instead of using `pactree` to determine
the dependency tree, I use `pacman` directly and crawl the tree myself.

This has a slightly increased maintainence load (there are two packages
with different names in different places for some reason). But it means
that I can exclude any subtree I like. Currently:

mingw-w64-x86_64-librsvg

brings in

mingw-w64-x86_64-glib2

which brings in lots of stuff including python. Excluding this results
in a much smaller dependencies package (around 40Mb as opposed to
140Mb). Haven't build the final files yet, but I would guess that this
would bring the installer version down to 50Mb -- not quite "eight Mb and
constantly swapping", but pretty small.

This also opens up the question of whether we *should* include any
executables that would add value to Emacs on Windows; I hesitate to go
too far down this route, mostly because maintaining an mini MSYS2
distribution seems the wrong thing to do.

But some basic functionality that other editors get from the OS comes
from external packages. I am thinking gzip, find, grep and aspell as
essential. Things like latex and python, I would exclude. Then there is
some middle ground -- I use msmtp for sending email, for instance.

The branch is here. Comments welcome.

http://git.savannah.gnu.org/cgit/emacs.git/log/?h=feature/smaller-windows

Phil