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/visualizecontrolcodes_test.c

@@ -16,24 +16,34 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/runtime/gc.internal.h"
 #include "libc/testlib/ezbench.h"
 #include "libc/testlib/hyperion.h"
 #include "libc/testlib/testlib.h"
-#include "net/http/http.h"
+#include "libc/x/x.h"
+#include "net/http/escape.h"
 
 TEST(VisualizeControlCodes, test) {
-  EXPECT_STREQ("hello", VisualizeControlCodes("hello", -1, 0));
-  EXPECT_STREQ("hello\r\n", VisualizeControlCodes("hello\r\n", -1, 0));
-  EXPECT_STREQ("hello␁␂␡", VisualizeControlCodes("hello\1\2\177", -1, 0));
-  EXPECT_STREQ("hello\\u0085", VisualizeControlCodes("hello\302\205", -1, 0));
+  EXPECT_STREQ("hello", gc(VisualizeControlCodes("hello", -1, 0)));
+  EXPECT_STREQ("hello\r\n", gc(VisualizeControlCodes("hello\r\n", -1, 0)));
+  EXPECT_STREQ("hello␁␂␡", gc(VisualizeControlCodes("hello\1\2\177", -1, 0)));
+  EXPECT_STREQ("hello\\u0085",
+               gc(VisualizeControlCodes("hello\302\205", -1, 0)));
 }
 
 TEST(VisualizeControlCodes, testOom_returnsNullAndSetsSizeToZero) {
   size_t n = 31337;
-  EXPECT_EQ(NULL, VisualizeControlCodes("hello", 0x1000000000000, &n));
+  EXPECT_EQ(NULL, gc(VisualizeControlCodes("hello", 0x1000000000000, &n)));
   EXPECT_EQ(0, n);
 }
 
+TEST(VisualizeControlCodes, testWeirdHttp) {
+  size_t n = 31337;
+  char *p, B[] = "\0GET /redbean.lua\n\n";
+  ASSERT_NE(0, (p = gc(VisualizeControlCodes(B, sizeof(B), &n))));
+  EXPECT_STREQ("\"␀GET /redbean.lua\\n\\n␀\"", gc(xasprintf("%`'.*s", n, p)));
+}
+
 BENCH(VisualizeControlCodes, bench) {
   EZBENCH2("VisualizeControlCodes", donothing,
            free(VisualizeControlCodes(kHyperion, kHyperionSize, 0)));