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/decodelatin1.c

@@ -20,28 +20,35 @@
 #include "libc/intrin/pmovmskb.h"
 #include "libc/mem/mem.h"
 #include "libc/str/str.h"
-#include "net/http/http.h"
+#include "net/http/escape.h"
 
 /**
  * Decodes ISO-8859-1 to UTF-8.
  *
- * @param data is input value
- * @param size if -1 implies strlen
- * @param out_size if non-NULL receives output length
+ * @param p is input value
+ * @param n if -1 implies strlen
+ * @param z if non-NULL receives output length
  * @return allocated NUL-terminated buffer, or NULL w/ errno
  */
-char *DecodeLatin1(const char *data, size_t size, size_t *out_size) {
+char *DecodeLatin1(const char *p, size_t n, size_t *z) {
   int c;
-  size_t n;
+  size_t i;
   char *r, *q;
-  const char *p, *e;
-  if (size == -1) size = data ? strlen(data) : 0;
-  if ((r = malloc(size * 2 + 1))) {
-    q = r;
-    p = data;
-    e = p + size;
-    while (p < e) {
-      c = *p++ & 0xff;
+  int8_t v1[16], v2[16], vz[16];
+  if (z) *z = 0;
+  if (n == -1) n = p ? strlen(p) : 0;
+  if ((q = r = malloc(n * 2 + 1))) {
+    for (i = 0; i < n;) {
+      memset(vz, 0, 16); /* 3x speedup for ASCII */
+      while (i + 16 < n) {
+        memcpy(v1, p + i, 16);
+        pcmpgtb(v2, v1, vz);
+        if (pmovmskb((void *)v2) != 0xFFFF) break;
+        memcpy(q, v1, 16);
+        q += 16;
+        i += 16;
+      }
+      c = p[i++] & 0xff;
       if (c < 0200) {
         *q++ = c;
       } else {
@@ -49,14 +56,9 @@ char *DecodeLatin1(const char *data, size_t size, size_t *out_size) {
         *q++ = 0200 | c & 077;
       }
     }
-    n = q - r;
+    if (z) *z = q - r;
     *q++ = '\0';
-    if ((q = realloc(r, n + 1))) r = q;
-  } else {
-    n = 0;
-  }
-  if (out_size) {
-    *out_size = n;
+    if ((q = realloc(r, q - r))) r = q;
   }
   return r;
 }