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

test/net/http/decodelatin1_test.c

@@ -16,10 +16,11 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/errno.h"
 #include "libc/testlib/ezbench.h"
 #include "libc/testlib/hyperion.h"
 #include "libc/testlib/testlib.h"
-#include "net/http/http.h"
+#include "net/http/escape.h"
 
 size_t n;
 
@@ -27,6 +28,30 @@ TEST(DecodeLatin1, test) {
   EXPECT_STREQ("", DecodeLatin1(NULL, 0, 0));
   EXPECT_STREQ("¥atta", DecodeLatin1("\245atta", -1, &n));
   EXPECT_EQ(6, n);
+  EXPECT_STREQ("\245atta", EncodeLatin1("¥atta", -1, &n, 0));
+  EXPECT_EQ(5, n);
+}
+
+TEST(DecodeLatin1, testAbleToImposeCharacterRestrictions) {
+  errno = 0;
+  EXPECT_EQ(0, EncodeLatin1("\200atta", -1, &n, kControlC1));
+  EXPECT_EQ(0, n);
+  EXPECT_EQ(EILSEQ, errno);
+  errno = 0;
+  EXPECT_EQ(0, EncodeLatin1("\002atta", -1, &n, kControlC0));
+  EXPECT_EQ(0, n);
+  EXPECT_EQ(EILSEQ, errno);
+}
+
+TEST(EncodeLatin1, roundTrip) {
+  int i;
+  char b[256];
+  for (i = 0; i < 256; ++i) b[i] = i;
+  char *utf8 = DecodeLatin1(b, 256, &n);
+  EXPECT_EQ(384, n);
+  char *lat1 = EncodeLatin1(utf8, n, &n, 0);
+  ASSERT_EQ(256, n);
+  EXPECT_EQ(0, memcmp(b, lat1, 256));
 }
 
 TEST(DecodeLatin1, testOom_returnsNullAndSetsSizeToZero) {
@@ -38,4 +63,6 @@ TEST(DecodeLatin1, testOom_returnsNullAndSetsSizeToZero) {
 BENCH(DecodeLatin1, bench) {
   EZBENCH2("DecodeLatin1", donothing,
            DecodeLatin1(kHyperion, kHyperionSize, 0));
+  EZBENCH2("EncodeLatin1", donothing,
+           EncodeLatin1(kHyperion, kHyperionSize, 0, 0));
 }