Add epoll and do more release readiness changes

This change also pays off some of the remaining technical debt with
stdio, file descriptors, and memory managemnt polyfills.

libc/zipos/parseuri.c

@@ -18,7 +18,7 @@
 │ 02110-1301 USA                                                               │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/str/str.h"
-#include "libc/zipos/zipos.h"
+#include "libc/zipos/zipos.internal.h"
 
 const char kZiposSchemePrefix[4] = "zip:";