This code has not been updated since 2016, and it looks like it has
rotted quite a bit since. It does not build against the current set
of phoenix sources -- I had to hack both the kernel headers and the
newlib headers up to get it to build, and I still have no idea if it
actually links or runs. It seems like the project itself has moved
away from newlib and to its own C library:
https://phoenix-rtos.com/documentation/libc/README.md
So since there's no interest from the phoenix folks to maintain this,
and it has a significant amount of non-standard code that we try to
keep up-to-date (without actually testing it), just punt it all.
Convert all the libc/ subdir makes into the top-level Makefile. This
allows us to build all of libc from the top Makefile without using any
recursive make calls. This is faster and avoids the funky lib.a logic
where we unpack subdir archives to repack into a single libc.a. The
machine override logic is maintained though by way of Makefile include
ordering, and source file accumulation in libc_a_SOURCES.
There's a few dummy.c files that are no longer necessary since we aren't
doing the lib.a accumulating, so punt them.
The winsup code has been pulling the internal newlib ssp library out,
but that doesn't exist anymore, so change that to pull the objects.
This kills off the last configure script under libc/ and folds it
into the top newlib configure script. The a lot of the logic was
already in the top configure script, so move what's left into a
libc/acinclude.m4 file.