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/nt/struct/objectattributes.h

@@ -1,13 +1,12 @@
 #ifndef COSMOPOLITAN_LIBC_NT_I_OBJECTATTRIBUTES_H_
 #define COSMOPOLITAN_LIBC_NT_I_OBJECTATTRIBUTES_H_
+#include "libc/nt/struct/rtluserprocessparameters.h"
+#include "libc/nt/struct/securityattributes.h"
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 
-struct NtUnicodeString;
-struct NtSecurityDescriptor;
-
 struct NtObjectAttributes {
   uint32_t Length;
-  void *RootDirectory;
+  int64_t RootDirectory;
   struct NtUnicodeString *ObjectName;
   uint32_t Attributes; /* OBJ_INHERIT, etc. */
   struct NtSecurityDescriptor *SecurityDescriptor;