[PATCH]: Don't XFAIL 21674.cc on darwin

[Paolo Bonzini]

>> Hum, the idea is fine; I'm unfamiliar with the construct.  I've seen it 
>> spelled this way:
>>
>>   target { ! { powerpc*-*-darwin* hppa*-*-hpux* ia64-*-hpux* } }
>>
>> not not sure about that spelling.  Ok if you're sure or find someone to 
>> confirm it.
> 
> Mike,
>    The testsuite/22_locale/ctype/is/char/2.cc testcase uses this form
> of a negative match...
> 
> // { dg-do run { xfail *-*-![linux]* } }
> 
> 
> ...so unless that testcase is broken, the use of 'xfail *-*-![darwin]*'
> should be equally valid.

I agree that the syntax seemed weird and I had never seen it, and that
I'd rather find the spelling similar to Mike's proposed one in other
testcases, and use it.  Maybe fixing the other example you found, too. :-)

Paolo