[Bug other/78161] contrib/download_prerequisites fails on MacOS, Lubuntu, and Windows

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78161

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
The issue with the current script is probably relying too much on wget
internals
(the -O option).  It would probably be better to simply cd into the destination
directory and do wget w/o -O.