> An alternative would be:
* get those other applications fixed;
Really? If you answer to a real-world problem is "fix the world" why even bother answering?
> * for this part of the change to be reverted in Emacs;
>
> * for me to set the correct environment var from the Windows shortcut
> that points to runemacs.exe. Can it be done easily?
Easiest is probably to change it to run a .cmd file that sets the
variable and then runs runemacs.exe, if you don’t mind a useless
console window. If you do, you’ll probably need to write and compile a
(GUI-targeted but windowless) program in a language of your choice,
that runs runemacs.exe with a modified environment.
At
which point I might as well fix it in my Emacs config, which has ample
facilities for this, and which I would do if this weren't such an early
thing.