Make more threading improvements

- ASAN memory morgue is now lockless
- Make C11 atomics header more portable
- Rewrote pthread keys support to be lockless
- Simplify Python's unicode table unpacking code
- Make crash report write(2) closer to being atomic
- Make it possible to strace/ftrace a single thread
- ASAN now checks nul-terminated strings fast and properly
- Windows fork() now restores TLS memory of calling thread

third_party/zlib/puff.c

@@ -158,7 +158,7 @@ struct state {
  *   buffer, using shift right, and new bytes are appended to the top of the
  *   bit buffer, using shift left.
  */
-local int bits(struct state *s, int need)
+local noinstrument int bits(struct state *s, int need)
 {
     long val;           /* bit accumulator (can use up to 20 bits) */