Get Cosmopolitan into releasable state

A new rollup tool now exists for flattening out the headers in a way
that works better for our purposes than cpp. A lot of the API clutter
has been removed. APIs that aren't a sure thing in terms of general
recommendation are now marked internal.

There's now a smoke test for the amalgamation archive and gigantic
header file. So we can now guarantee you can use this project on the
easiest difficulty setting without the gigantic repository.

A website is being created, which is currently a work in progress:
https://justine.storage.googleapis.com/cosmopolitan/index.html

libc/calls/kill.c

@@ -40,10 +40,15 @@
  * @asyncsignalsafe
  */
 int kill(int pid, int sig) {
-  if (pid == getpid()) return raise(sig);
+  int me;
   if (!IsWindows()) {
     return kill$sysv(pid, sig, 1);
   } else {
-    return enosys();
+    me = getpid();
+    if (!pid || pid == me || pid == -me) {
+      return raise(sig);
+    } else {
+      return enosys();
+    }
   }
 }