bug#73159: 30.0.90; uniscribe / harfbuzz are not initialized on Windows, resulting in fallback to gdi

[Eli Zaretskii <eliz@gnu.org>]

> From: Casey Banner <kcbanner@gmail.com>
> Date: Tue, 10 Sep 2024 14:31:07 -0400
> Cc: 73159@debbugs.gnu.org
> 
> > How come your LANG is set to en_US.UTF-8?  Did you set this in the
> > environment or something.  Using UTF-8 as the default encoding on
> > Windows is not a good idea.
> 
> It seems that the msys2 .profile has `export LANG=$(locale -uU)`, and that returns en_US.UTF-8 for me.

I don't recommend running Emacs from the MSYS2 Bash prompt.  Instead,
run it from a desktop shortcut or pin it to the task bar and run from
there.

> > Please look at src/epaths.h and see how PATH_EXEC is defined there. 
> 
> It is indeed  #define PATH_EXEC "%emacs_dir%/libexec/emacs/30.0.50/x86_64-w64-mingw32"
> 
> src/epaths.in has #define PATH_EXEC "/usr/local/libexec/emacs" 
> 
> I had been running configure and make in a subdirectory. If I run them in the top-level directory, 
> then it does update PATH_EXEC to the correct version. I think I made the wrong assumption that
>  running configure in a subdirectory would leave the main source clean.
> 
> Thank you for your help debugging this!

OK, so that's one mystery down.  We are left with the HarfBuzz issue;
please answer the questions I asked about that.