[LTP] Test library API changes

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
Since we successfuly released LTP I've restored the effort to create
better test library, updated changes are at:

https://github.com/metan-ucw/ltp

There are couple of smaller changes:

* The minimal kernel version is now stored in tst_test structure
  (which avoids calling tst_kvercmp() in setup())

* The tst_resm() and tst_brkm() are now rerouted to new library
  in case that test was started using the new library and in case
  that cleanup is NULL for tst_brkm().

  Now the SAFE_MACROS() and rest of the library calls works from newlib
  tests as well. Though most of the library calls would end up with
  wrappers without the cleanup callback just like I did for the
  SAFE_MACROS() allready.

* Unless TST_NO_DEFAULT_MAIN is defined the tst_test.h adds default main
  that picks up struct tst_test named test and run the tests.

* tst_syscall() has been added since the ltp_syscall() quietly adds
  cleanup parameter to tst_brkm()


There are two more tests converted:

https://github.com/metan-ucw/ltp/blob/master/testcases/kernel/syscalls/add_key/add_key01.c
https://github.com/metan-ucw/ltp/blob/master/testcases/kernel/syscalls/add_key/add_key02.c

And preadv test is updated:

https://github.com/metan-ucw/ltp/blob/master/testcases/kernel/syscalls/preadv/preadv01.c


My current plan is to try to convert a few more testcases and edhance
the new lib API on the go, then work more on the library internals that
are pretty minimalistic at the moment.

-- 
Cyril Hrubis
chrubis@suse.cz