* raimo/diffserv-socket-option/OTP-13582:
  Tune 'tclass' semantics
  Implement IPV6_TCLASS

Normally, calling code:delete/1 before re-loading the code for a
module is unnecessary but causes no problem.

But there will be be problems if the new code has an on_load function.
Code with an on_load function will always be loaded as old code
to allowed it to be easily purged if the on_load function would fail.
If the on_load function succeeds, the old and current code will be
swapped.

So in the scenario where code:delete/1 has been called explicitly,
there is old code but no current code. Loading code with an
on_load function will cause the reference to the old code to be
overwritten. That will at best cause a memory leak, and at worst
an emulator crash (especially if NIFs are involved).

To avoid that situation, we will put the code with the on_load
function in a special, third slot in Module.

ERL-240

* lukas/kernel/os_cmd_fix_stdin_close/OTP-13867:
  kernel: Close stdin of commands run in os:cmd

This is needed when running programs that only exit when
stdin has been closed, e.g. 'more'.

We don't want the infinite loop as it leaks after the test finished.

* rickard/ds-purge-module/OTP-13808:
  Perform check_process_code while process is executing dirty

Conflicts:
	erts/doc/src/erl_nif.xml

* rickard/fun-purge-bug/OTP-13809:
  Fix purge of code
  Reclaim literal area after purge has completed
  Separate literal area from code

Conflicts:
	erts/doc/src/erlang.xml
	erts/emulator/beam/beam_bif_load.c
	erts/emulator/beam/erl_init.c
	erts/preloaded/ebin/init.beam