Improve locks and signals

- Introduce fast spinlock API
- Double rand64() perf w/ spinlock
- Improve raise() on New Technology
- Support gettid() across platforms
- Implement SA_NODEFER on New Technology
- Move the lock intrinsics into LIBC_INTRIN
- Make SIGTRAP recoverable on New Technology
- Block SIGCHLD in wait4() on New Technology
- Add threading prototypes for XNU and FreeBSD
- Rewrite abort() fixing its minor bugs on XNU/NT
- Shave down a lot of the content in libc/bits/bits.h
- Let signal handlers modify CPU registers on New Technology

net/https/sslcache.c

@@ -21,6 +21,7 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/struct/stat.h"
 #include "libc/errno.h"
+#include "libc/intrin/lockcmpxchg.h"
 #include "libc/log/check.h"
 #include "libc/log/log.h"
 #include "libc/macros.internal.h"
@@ -129,7 +130,7 @@ int UncacheSslSession(void *data, mbedtls_ssl_session *session) {
   ts = time(0);
   if (!(e->time <= ts && ts <= e->time + cache->lifetime)) {
     DEBUGF("%u sslcache expired", i);
-    lockcmpxchg(&e->tick, tick, 0);
+    _lockcmpxchg(&e->tick, tick, 0);
     return 1;
   }
   cert = 0;
@@ -199,7 +200,7 @@ int CacheSslSession(void *data, const mbedtls_ssl_session *session) {
   e->time = time(0);
   tick = rdtsc();
   asm volatile("" ::: "memory");
-  if (tick && lockcmpxchg(&e->pid, pid, 0)) {
+  if (tick && _lockcmpxchg(&e->pid, pid, 0)) {
     DEBUGF("%u saved %s%s %`#.*s", i,
            mbedtls_ssl_get_ciphersuite_name(session->ciphersuite),
            session->compression ? " DEFLATE" : "", session->id_len,