[PATCH] D11777: [Target/X86] Allow LowerVAARG to work on FreeBSD, too.

[Joerg Sonnenberger via llvm-commits]

On Wed, Aug 05, 2015 at 08:56:22PM +0000, Charles Davis wrote:
> This change enables the `va_arg` instruction to work on
> FreeBSD/amd64, too. It's needed to prevent test failures after D1622
> lands. Since FreeBSD/amd64 largely follows the System V ABI for x86-64
> (like Linux/x86-64), I don't see any reason why this wouldn't work.

Makes me wonder if the OS check is not just the wrong approach. So what
does it actually want to have here?

Joerg