This brings the alsa driver in line with the jack render (progress
towards #16), but breaks most of the other drivers (for now: one step at
a time). The idea is that once the pull model is working for at least
one other target, the jack renderer can become just another target like
it should have been in the first place (but I needed to get the pull
model working first, then forgot about it).
Correct state checking is not done yet, but testsound does produce what
seems to be fairly good sound when it starts up correctly (part of the
state checking (or lack thereof), I imagine).
It now takes a context pointer (opaque data) that holds the buffers it
uses for the temporary strings. If the context pointer is null, a static
context is used (making those uses of va NOT thread-safe). Most calls to
va use the static context, but all such calls have been formatted
consistently so they are easy to find when it comes time to do a full
audit.
They take a pointer to a free-list used for hashlinks so the hashlink
pools can be per-thread. However, hash tables that are not updated are
always thread-safe, so this affects only updates. progs_t has been set
up such that it is easy for multiple progs within one thread can share
hashlinks.
This happens when qf fails to connect to jackd (possibly other times).
There is probably a better solution to the problem, but not opening a
stream when the sample rate is reported as 0 definitely fixes the inifinite
recursion in read_samples().
the resampler is being badly abused for streams, and it's not yet properly
autoconfiscated, but things are working. Better yet, at the correct pitch and
speed.
