Implement raw system call for redbean lua code

You can now call functions like fork() from Lua and it'll work across
all supported platforms, including Windows. This gives you a level of
control of the system that Lua traditionally hasn't been able to have
due to its focus on old portable stdio rather modern POSIX APIs. Demo
code has been added to redbean-demo.com to show how it works.

This change also modifies Lua so that integer literals with a leading
zero will be interpreted as octal. That should help avoid shooting in
the foot with POSIX APIs that frequently use octal mode bits.

This change fixes a bug in opendir(".") on New Technology.

Lastly, redbean will now serve crash reports to private network IPs.
This is consistent with other frameworks. However that isn't served
to public IPs unless the -E flag is passed to redbean at startup.

libc/sock/socketpair.c

@@ -25,7 +25,9 @@
  * Creates bidirectional pipe.
  *
  * @param family should be AF_UNIX or synonymously AF_LOCAL
- * @param type may be or'd with SOCK_CLOEXEC
+ * @param type can be SOCK_STREAM (for TCP), SOCK_DGRAM (e.g. UDP), or
+ *     SOCK_RAW (IP) so long as IP_HDRINCL was passed to setsockopt();
+ *     and additionally, may be or'd with SOCK_NONBLOCK, SOCK_CLOEXEC
  * @param sv a vector of 2 integers to store the created sockets
  * @return 0 if success, -1 in case of error
  * @error EFAULT, EPFNOSUPPORT, etc.