Add /statusz page to redbean plus other enhancements

redbean improvements:

- Explicitly disable corking
- Simulate Python regex API for Lua
- Send warmup requests in main process on startup
- Add Class-A granular IPv4 network classification
- Add /statusz page so you can monitor your redbean's health
- Fix regressions on OpenBSD/NetBSD caused by recent changes
- Plug Authorization header into Lua GetUser and GetPass APIs
- Recognize X-Forwarded-{For,Host} from local reverse proxies
- Add many additional functions to redbean Lua server page API
- Report resource usage of child processes on `/` listing page
- Introduce `-a` flag for logging child process resource usage
- Introduce `-t MILLIS` flag and `ProgramTimeout(ms)` init API
- Introduce `-H "Header: value"` flag and `ProgramHeader(k,v)` API

Cosmopolitan Libc improvements:

- Make strerror() simpler
- Make inet_pton() not depend on sscanf()
- Fix OpenExecutable() which broke .data section earlier
- Fix stdio in cases where it overflows kernel tty buffer
- Fix bugs in crash reporting w/o .com.dbg binary present
- Add polyfills for SO_LINGER, SO_RCVTIMEO, and SO_SNDTIMEO
- Polyfill TCP_CORK on BSD and XNU using TCP_NOPUSH magnums

New netcat clone in examples/nc.c:

While testing some of the failure conditions for redbean, I noticed that
BusyBox's `nc` command is pretty busted, if you use it as an interactive
tool, rather than having it be part of a pipeline. Unfortunately this'll
only work on UNIX since Windows doesn't let us poll on stdio and sockets
at the same time because I don't think they want tools like this running
on their platform. So if you want forbidden fruit, it's here so enjoy it

net/http/visualizecontrolcodes.c

@@ -20,7 +20,7 @@
 #include "libc/str/str.h"
 #include "libc/str/thompike.h"
 #include "libc/str/tpenc.h"
-#include "net/http/http.h"
+#include "net/http/escape.h"
 
 /**
  * Filters out control codes from string.
@@ -29,6 +29,10 @@
  * want full blown C string literal escaping, but we don't want things
  * like raw ANSI control codes from untrusted devices in our terminals.
  *
+ * This function also canonicalizes overlong encodings. Therefore it
+ * isn't necessary to say VisualizeControlCodes(Underlong(𝑥))) since
+ * VisualizeControlCodes(𝑥) will do the same thing.
+ *
  * @param data is input value
  * @param size if -1 implies strlen
  * @param out_size if non-NULL receives output length