This change extends the existing in-tree test infrastructure such
that it can also be run as part of a the installed package. This
simplifies testing on multiple systems and is generally all around
useful. The scripts may still be run in-tree and will use the
in-tree build products as long as .script-config exists.
Modern kernel build systems at least post 2.6.16 will set this properly
so we should not. In fact post 2.6.28 the include headers have moved
under arch so the guess we make here is completely wrong. Letting
the kernel build system set this ensure it will be correct. Also
drop the ulimit from the Makefile which, not surprisingly, turns out
to be very non-portable. If your expecting failures set the ulimit
in your shell before kicking off the test suite.