Make fixes and improvements

- Introduce __assert_disable global
- Improve strsignal() thread safety
- Make system call tracing thread safe
- Fix SO_RCVTIMEO / SO_SNDTIMEO on Windows
- Refactor DescribeFoo() functions into one place
- Fix fork() on Windows when TLS and MAP_STACK exist
- Round upwards in setsockopt(SO_RCVTIMEO) on Windows
- Disable futexes on OpenBSD which seem extremely broken
- Implement a better kludge for monotonic time on Windows

third_party/linenoise/linenoise.c

@@ -773,7 +773,9 @@ static ssize_t linenoiseRead(int fd, char *buf, size_t size,
     }
     if (gotcont && rawmode != -1) {
       rawmode = -1;
+      --__strace;
       linenoiseEnableRawMode(0);
+      ++__strace;
       if (l) refreshme = 1;
     }
     if (l && gotwinch) refreshme = 1;