Hi Nick,

A few days ago, I've tried to open
https://sourceware.org/bugzilla/show_bug.cgi?id=25713
again because the new handling of Windows filename is triggering
issues for GNAT under MinGW.

We've made the following changes attached. We aren't sure this
is the best solution, but it seems to work fine and it's what MinGW is
using internally.
If you find such a patch ok, I guess it would be logical to merge it
for 2.39.

Thanks in advance
Clément