support for calling Linux syscalls directly

[chrubis@suse.cz]

Hi!
> I have had a number of discussions with people on this topic,
> especially given that syscall(3) is fundamentally flawed on a number
> of architectures, and that some architectures have been forced to use
> nonstandard signatures, complicating things.

I do the LTP[1] which makes legitimate use of syscall(3) as for the
testing purposes we need to be able to call bare syscalls in order to
validate both glibc and kernel API. And removing the call would mess
backward compatibility.

Having suitable replacements in glibc wouldn't help much as we would
need either to add #ifdefs into each test that uses it or carry a copy
of the syscall wrappers inside the LTP.

1: https://github.com/linux-test-project/ltp

-- 
Cyril Hrubis
chrubis@suse.cz