Lock each directory before entering it so when using -j, the same
dependency isn't built more than once at a time.
This doesn't get full -j parallelism though, since one make child
will be sitting idle waiting for flock to receive its lock and
continue making (which should then do nothing since it will have
been built already). Unfortunately there's not much that can be
done to fix that since it can't proceed until its dependency is
built by another make process.
Instead of directly manipulating LDFLAGS, set LIB_DEPS in each
subdirectory Makefile listing the libraries needed for
building/linking such as "LIB_DEPS = Core GUI Draw IPC Core".
This adds each library as an -L and -l argument in LDFLAGS, but
also adds the library.a file as a link dependency on the current
$(PROGRAM). This causes the given library to be (re)built before
linking the current $(PROGRAM), but will also re-link any binaries
depending on that library when it is modified, when running make
from the root directory.
Also turn generator tools like IPCCompiler into dependencies on the
files they generate, so they are built on-demand when a particular
directory needs them.
This all allows the root Makefile to just list directories and not
care about the order, as all of the dependency tracking will figure
it out.
Allow everything to be built from the top level directory with just
'make', cleaned with 'make clean', and installed with 'make
install'. Also support these in any particular subdirectory.
Specifying 'make VERBOSE=1' will print each ld/g++/etc. command as
it runs.
Kernel and early host tools (IPCCompiler, etc.) are built as
object.host.o so that they don't conflict with other things built
with the cross-compiler.
The center of this is now an ABuffer class in LibAudio.
ABuffer contains ASample, which has two channels (left/right) in
floating point for mixing purposes, in 44100hz.
This means that the loaders (AWavLoader in this case) needs to do some
manipulation to get things in the right format, but that we don't need
to care after format loading is done.
While we're at it, do some correctness fixes. PCM data is unsigned if
it's 8 bit, but 16 bit is signed. And /dev/audio also wants signed 16
bit audio, so give it what it wants.
On top of this, AudioServer now accepts requests to play a buffer.
The IPC mechanism here is pretty much a 1:1 copy-paste from
LibGUI/WindowServer. It can be generalized more in the future, but for
now I want to get AudioServer working decently first :)
Additionally, add a little "aplay" tool to load and play a WAV file. It
will break with large WAVs (run out of memory, heh...) but it's a start.
Future work needs to make AudioServer block buffer submission from
clients until it has played the buffer they are requesting to play.
* Add a LibAudio, and move WAV file parsing there (via AWavFile and AWavLoader)
* Add CLocalSocket, and CSocket::connect() variant for local address types.
We make some small use of this in WindowServer (as that's where we
modelled it from), but don't get too invasive as this PR is already
quite large, and the WS I/O is a bit carefully done
* Add an AClientConnection which will eventually be used to talk to
AudioServer (and make use of it in Piano, though right now it really
doesn't do anything except connect, using our new CLocalSocket...)
