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/encodebase64.c

@@ -18,7 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/mem/mem.h"
 #include "libc/str/str.h"
-#include "net/http/base64.h"
+#include "net/http/escape.h"
 
 #define CHARS "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
 
@@ -30,7 +30,7 @@
  * @param out_size if non-NULL receives output length
  * @return allocated NUL-terminated buffer, or NULL w/ errno
  */
-char *EncodeBase64(const void *data, size_t size, size_t *out_size) {
+char *EncodeBase64(const char *data, size_t size, size_t *out_size) {
   size_t n;
   unsigned w;
   char *r, *q;
@@ -39,7 +39,7 @@ char *EncodeBase64(const void *data, size_t size, size_t *out_size) {
   if ((n = size) % 3) n += 3 - size % 3;
   n /= 3, n *= 4;
   if ((r = malloc(n + 1))) {
-    for (q = r, p = data, pe = p + size; p < pe; p += 3) {
+    for (q = r, p = (void *)data, pe = p + size; p < pe; p += 3) {
       w = p[0] << 020;
       if (p + 1 < pe) w |= p[1] << 010;
       if (p + 2 < pe) w |= p[2] << 000;