Ignore SIGWINCH during replay.
Only set PTHREAD_MUTEX_NO_ELISION_NP for mutex types where glibc might set it (PTHREAD_MUTEX_TIMED_NP).

Setting PTHREAD_MUTEX_NO_ELISION_NP for recursive mutexes causes glibc to
misbehave. In particular pthread_cond_wait calls
__pthread_mutex_cond_lock_adjust which does not handle recursive mutexes
properly if they have elision flags set.

Resolves #1241.
Check and print mismatches on $orig_eax register.

This contains the syscall number for syscall events, and it's important to
check that!
Work around kernel issue where $orig_eax is cleared when some interrupted
syscalls are continued more than once.

The previous commit to check $orig_eax for divergence exposed this issue.

Some syscall_conts clear $orig_eax (for unclear reasons). We just restore it
if necessary after those calls.
Bump trace version number since most old traces are unreplayable due to $orig_eax checks.
Use pthread_mutex_ shims in preload.c to disable priority-inheriting mutexes, and drop support for kernel PI futex operations.

The PI futex operations are very hard to support reliably in rr. rr's scheduler
is not PI aware so these operations have no purpose.

Resolves #1248.
Remove unused futex sync mechanism.
Remove unused seccomp-bpf declarations.
Restore tracee siginfo after goto_a_happy_place may have caused the kernel to forget it.

Resolves #1250.
Don't coalesce SCHED events over an event we're waiting for.