When pthread_t was smaller, our calculated thread IDs would include
uninitialized RAM, and so our unit tests would fail because thread_ids
would never match one another.
When pthread_t was larger and alignment was big-endian, our calculated
thread IDs would only have the most significant bytes of the
pthread_t, when in practice all the entropy is in the low-order bytes.
Found with help from Dagobert Michelsen.
The interface from the user's POV is similar to the locking
implementation: either provide a structure full of function
pointers, or just call evthread_use_*_threads() and everything will
be okay.
The internal interface is meant to vaguely resemble pthread_cond_*,
which Windows people will better recognize as *ConditionVariable*.
Previously, there was no good way to request different kinds of lock
(say, read/write vs writeonly or recursive vs nonrecursive), or for a
lock function to signal failure (which would be important for a
trylock mode).
This patch revises the lock API to be a bit more useful. The older
lock calls are still supported for now.
We also add a debugging mode to catch common errors in using the
locking APIs.
a) this is 2009
b) niels and nick have been comaintainers for a while
c) saying "all rights reserved" when you then go on to explicitly
disclaim some rights is sheer cargo-cultism.
svn:r1065
