[Bug testsuite/124011] Checking for target supports -fstack-protector fails on mingw

[nightstrike at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124011

--- Comment #3 from nightstrike <nightstrike at gmail dot com> ---
(In reply to nightstrike from comment #2)
> Created attachment 63615 [details]
> possible starting point patch
> 
> Attached a patch that works, hopefully it helps.

Note that this adds -Wno-stringop-overflow, because apparently warnings cause
tests to be unsupported.  Maybe someone knows a better solution here.