[PATCH] clang-check should ignore -no-integrated-as because certain drivers can't handle it

[Artyom Skrobov]

>> r194968 (reviewed at http://llvm-reviews.chandlerc.com/D2039) has 
>> changed the behaviour of clang-check w.r.t. -no-integrated-as argument:
>> previously, it was silently ignored; now, it's used to create the 
>> Compilation, and then ignored further down the flow.
>> 
>> r194992 had to XFAIL test/Tooling/multi-jobs.cpp on the grounds that 
>> "MSVC targeted drivers (*-win32) are incapable of invoking external
>> assembler." These drivers cannot create the Compilation when
>> -no-integrated-as argument is present.
>> 
>> Our patch restores the original behaviour, that is, silently ignoring 
>> -no- integrated-as. This allows to un-XFAIL test/Tooling/multi-jobs.cpp.
>> 
>> OK to commit?
>
> Is clang-check the only use of
> FixedCompilationDatabase::loadFromCommandLine()?

Yes, it's only used from CommonOptionsParser, and CommonOptionsParser is
only used in clang-check.

> Do we know why Clang::Tooling/multi-jobs.cpp has '--no-integrated-as' in
the
> first place?

No, but it's been there since the beginning (r156478).
I'm copying Simon Atanasyan and Manuel Klimek who created/reviewed the
original test, and may be able to shed some light on the purpose of
--no-integrated-as there.