build: remove library special cases

build: remove library special cases

The EAL and compat libraries were special-cases in the library build
process, the former because of it's complexity, and the latter because
it only consists of a single header file.

By reworking the EAL meson.build files, we can eliminate the need for it to
be a special case, by having it build up and return the list of sources,
headers, and objects and return those to the higher level build file. This
should also simplify the building of EAL, as we can eliminate a number of
meson.build files that would no longer be needed, and have fewer, but
larger meson.build files (9 now vs 14 previous) - thereby making the logic
easier to follow and items easier to find.

Once done, we can pull eal into the main library loop, with some
modifications to support it. Compat can also be pulled it once we add in a
check to handle the case of an empty sources list.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>