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

libc/intrin/createsymboliclink.c

@@ -34,6 +34,6 @@ bool32 CreateSymbolicLink(const char16_t *lpSymlinkFileName,
   ok = __imp_CreateSymbolicLinkW(lpSymlinkFileName, lpTargetPathName, dwFlags);
   if (!ok) __winerr();
   NTTRACE("CreateSymbolicLink(%#hs, %#hs, %s) → %hhhd% m", lpSymlinkFileName,
-          lpTargetPathName, DescribeNtSymbolicLinkFlags(dwFlags), ok);
+          lpTargetPathName, DescribeNtSymlinkFlags(dwFlags), ok);
   return ok;
 }