[Bug libstdc++/61532] [4.10 regression] make_signed and make_unsigned wchar_t have started failing in the libstdc++ testsuite.

["ramana at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61532

--- Comment #3 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---

(In reply to Jonathan Wakely from comment #2)
> This is likely to also be failing on the 4.9 branch, since the weekend

I was about to add 4.9 but then couldn't find a link to post. 

(In reply to Jonathan Wakely from comment #1)
> Targets that define wchar_t as unsigned int are not conforming to the C++
> standard, which requires wchar_t to be a distinct type, not a typedef.

The standard appears to say in Section 3.9.1 (basic.fundamental) #5 that the 

"Type wchar_t shall have the same size, signedness, and alignment requirements
(3.11) as one of the other integral types, called its underlying type." 

That's my interpretation from n3337.

> 
> I can look into a hack to detect non-conforming targets, but probably not
> until next week.

Please do take a look. 

Ramana