[LTP] [0/3] openposix: Fix installation file layout

[Joerg Vehlow]

as described in my RFC, here is a first implementation of a fixed
installation layout for open posix tests.

I implemented this using autoconf, to be able to specify the
installation location of the tests.

If build standalone, the open posix tests are still installed to
/opt/open_posix_testsuite/{conformance,functional,stress}, but when
installed as part of ltp, they are installed to
/opt/ltp/testcases/open_posix_testsuite/*

Joerg