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/gethttpheader.gperf

@@ -9,63 +9,70 @@
 %readonly-tables
 %struct-type
 %define lookup-function-name LookupHttpHeader
-struct HttpHeaderSlot { char *name; char code; };
+struct thatispacked HttpHeaderSlot { char *name; char code; };
 %%
-Accept,                    kHttpAccept
-Accept-Charset,            kHttpAcceptCharset
-Accept-Encoding,           kHttpAcceptEncoding
-Accept-Language,           kHttpAcceptLanguage
-Age,                       kHttpAge
-Allow,                     kHttpAllow
-Authorization,             kHttpAuthorization
-Cache-Control,             kHttpCacheControl
-Chunked,                   kHttpChunked
-Link,                      kHttpLink
-Connection,                kHttpConnection
-Content-Base,              kHttpContentBase
-Content-Encoding,          kHttpContentEncoding
-Content-Language,          kHttpContentLanguage
-Content-Length,            kHttpContentLength
-Content-Location,          kHttpContentLocation
-Content-MD5,               kHttpContentMd5
-Content-Range,             kHttpContentRange
-Content-Type,              kHttpContentType
-Date,                      kHttpDate
-ETag,                      kHttpEtag
-Expires,                   kHttpExpires
-From,                      kHttpFrom
-Host,                      kHttpHost
-If-Match,                  kHttpIfMatch
-If-Modified-Since,         kHttpIfModifiedSince
-If-None-Match,             kHttpIfNoneMatch
-If-Range,                  kHttpIfRange
-If-Unmodified-Since,       kHttpIfUnmodifiedSince
-Keep-Alive,                kHttpKeepAlive
-Max-Forwards,              kHttpMaxForwards
-Pragma,                    kHttpPragma
-Proxy-Authenticate,        kHttpProxyAuthenticate
-Proxy-Authorization,       kHttpProxyAuthorization
-Proxy-Connection,          kHttpProxyConnection
-Range,                     kHttpRange
-Referer,                   kHttpReferer
-Transfer-Encoding,         kHttpTransferEncoding
-Upgrade,                   kHttpUpgrade
-User-Agent,                kHttpUserAgent
-Via,                       kHttpVia
-Location,                  kHttpLocation
-Public,                    kHttpPublic
-Retry-After,               kHttpRetryAfter
-Server,                    kHttpServer
-Vary,                      kHttpVary
-Warning,                   kHttpWarning
-WWW-Authenticate,          kHttpWwwAuthenticate
-Last-Modified,             kHttpLastModified
-Trailer,                   kHttpTrailer
-TE,                        kHttpTe
-DNT,                       kHttpDnt
-Expect,                    kHttpExpect
-Content-Disposition,       kHttpContentDisposition
-Content-Description,       kHttpContentDescription
-Origin,                    kHttpOrigin
-Upgrade-Insecure-Requests, kHttpUpgradeInsecureRequests
-URI,                       kHttpUri
+Accept,                           kHttpAccept
+Accept-Charset,                   kHttpAcceptCharset
+Accept-Encoding,                  kHttpAcceptEncoding
+Accept-Language,                  kHttpAcceptLanguage
+Age,                              kHttpAge
+Allow,                            kHttpAllow
+Authorization,                    kHttpAuthorization
+Cache-Control,                    kHttpCacheControl
+Chunked,                          kHttpChunked
+Link,                             kHttpLink
+Connection,                       kHttpConnection
+Content-Base,                     kHttpContentBase
+Content-Encoding,                 kHttpContentEncoding
+Content-Language,                 kHttpContentLanguage
+Content-Length,                   kHttpContentLength
+Content-Location,                 kHttpContentLocation
+Content-MD5,                      kHttpContentMd5
+Content-Range,                    kHttpContentRange
+Content-Type,                     kHttpContentType
+Date,                             kHttpDate
+ETag,                             kHttpEtag
+Expires,                          kHttpExpires
+From,                             kHttpFrom
+Host,                             kHttpHost
+If-Match,                         kHttpIfMatch
+If-Modified-Since,                kHttpIfModifiedSince
+If-None-Match,                    kHttpIfNoneMatch
+If-Range,                         kHttpIfRange
+If-Unmodified-Since,              kHttpIfUnmodifiedSince
+Keep-Alive,                       kHttpKeepAlive
+Max-Forwards,                     kHttpMaxForwards
+Pragma,                           kHttpPragma
+Proxy-Authenticate,               kHttpProxyAuthenticate
+Proxy-Authorization,              kHttpProxyAuthorization
+Proxy-Connection,                 kHttpProxyConnection
+Range,                            kHttpRange
+Referer,                          kHttpReferer
+Transfer-Encoding,                kHttpTransferEncoding
+Upgrade,                          kHttpUpgrade
+User-Agent,                       kHttpUserAgent
+Via,                              kHttpVia
+Location,                         kHttpLocation
+Public,                           kHttpPublic
+Retry-After,                      kHttpRetryAfter
+Server,                           kHttpServer
+Vary,                             kHttpVary
+Warning,                          kHttpWarning
+WWW-Authenticate,                 kHttpWwwAuthenticate
+Last-Modified,                    kHttpLastModified
+Trailer,                          kHttpTrailer
+TE,                               kHttpTe
+DNT,                              kHttpDnt
+Expect,                           kHttpExpect
+Content-Disposition,              kHttpContentDisposition
+Content-Description,              kHttpContentDescription
+Origin,                           kHttpOrigin
+Upgrade-Insecure-Requests,        kHttpUpgradeInsecureRequests
+URI,                              kHttpUri
+X-Csrf-Token,                     kHttpXCsrfToken
+X-Forwarded-For,                  kHttpXForwardedFor
+X-Forwarded-Host,                 kHttpXForwardedHost
+X-Forwarded-Proto,                kHttpXForwardedProto
+X-Requested-With,                 kHttpXRequestedWith
+Access-Control-Request-Method,    kHttpAccessControlRequestMethod
+Access-Control-Request-Headers,   kHttpAccessControlRequestHeaders