[LTP] subdir make with LTP

[Garrett C. <yan...@gm...>]

Hi Mike, Nate, and Subrata,
    Although some people may be unhappy with this change, I was
thinking of `breaking' subdirectory based make operations with LTP as
this would overcomplicate the make system logic a great deal with a
bunch of cookie cutter logic that will grow stale and become a pain to
maintain.
    Is this something that would be a desired feature moving forward
or something we can official drop?
    Subdir based Make would still function by specifying srcdir= on
the command line, but doing a bare command like the following:

    cd testcases/kernel/syscalls && make all

    would fail.
Thanks,
-Garrett