r258720 - [MSVC Compat] Only warn for unknown clang-cl arguments

[Joerg Sonnenberger via cfe-commits]

On Mon, Jan 25, 2016 at 09:14:52PM -0000, Ehsan Akhgari via cfe-commits wrote:
> Author: ehsan
> Date: Mon Jan 25 15:14:52 2016
> New Revision: 258720
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=258720&view=rev
> Log:
> [MSVC Compat] Only warn for unknown clang-cl arguments
> 
> Summary:
> MSVC's driver accepts all unknown arguments but warns about them.  clang
> by default rejects all unknown arguments.  This causes issues
> specifically with build systems such as autoconf which liberally pass
> things such as $LDFLAGS to the compiler and expect everything to work.
> This patch teaches clang-cl to ignore unknown driver arguments.

Is this really a good idea? Yes, there are many broken configure
scripts, but at the same point, this change makes it more difficult
to detect whether an option is supported.

Joerg