[Windows][Installer] Always use own xz

[Herbert Voss]

Am 21.05.19 um 07:13 schrieb Vladimir Lomov:
> Hello, this is a bug report.
>
> Yesterday I tried to help to install TeX Live on a notebook of a student
> and faced with weird behavior of install-tl-windows.bat. The notebook
> has a broken mingw (not sure msys or msys2) installation so xz.exe from
> it doesn't work.
>
> I thought that the installer on Windows always uses it's own wget.exe and
> xz.exe but seems I was wrong. Are there any particular reasons to use
> xz.exe and wget.exe found in PATH instead of own ones? If there are no
> reasons then I think it is a bug and should be fixed, otherwise it might
> give unexpected errors (I faced with that one).
>

you can set the environment variable

TEXLIVE_PREFER_OWN=1

Herbert