Eli Zaretskii (eliz@gnu.org):

> Configure-time test is not good enough, as the binary could then be
> run in a different environment.
> 
> How about making it case-insensitive for Cygwin as well?

I ended up implementing Pedro's suggestion (a run-time test) but it
does not work in the case of Cygwin; getenv/setenv acts as if we add a
case-sensitive environment, but we use CreateProcess to create the
inferior, so we end up with a case-insensitive environment for the
inferior. So making it case-insensitive is indeed what makes sense.

Last versions of the patch in attachment, along with the testcase.
Fully tested on x86_64-linux; partially tested on Cygwin (e.g. without
gdb.threads) amd mingw32 (testenv.exp only).

Any comments?