[PATCH] Fix compilation under MinGW

[Anton Yartsev]

Hi Takumi,
Thanks for looking at this!
Really, MinGW64 defines _fpclass as well as MinGW32.
I also found out that I am using precompiled TDM-GCC instead of authentic MinGW64.
Sorry for a hasty conclusion.

> Anton,
>
> Could you introduce fpclass stuff in any other headers?
> Excuse me, I cannot seek current version of mingw-w64 headers now.
>
> Or, I suggest it'd be better to check the format in %e (and presence
> of fpclass) in configuration.
>
>
>> +#if defined(_WIN32) && !defined(__MINGW32__) && !defined(__MINGW64__)
> I wonder why you were trying to exclude __MINGW32__ here. I assume
> traditional mingw32 should have such definitions, (and I suppose
> mingw-w64, as well.)
> Let me know which distro you are using.
>
>
>> Please review and apply (I have no commit access to llvm) if I guessed
>> correctly and the patch is helpful.
> You could commit llvm tree as well as clang. That said, review would
> be required for non-trivial changes.
> I guess your patch would cause failures in llvm unittests on mingw32.
>
>
> ...Takumi

-- 
Anton