* john/erts/spectre-configure-flag/OTP-15430/ERIERL-237:
  Allow disabling retpoline in interpreter loop
  Add a ./configure flag for spectre mitigation

* sverker/big-band-bug/ERL-804/OTP-15487:
  erts: Fix bug in 'band' of two negative numbers, one big

Similar bug as for bxor fixed by abc4fd372d476821448dfb9

Ex:
1> io:format("~.16B\n", [-16#1110000000000000000 band (-1)]).
-1120000000000000000

Wrong result for

(-X bsl WS) band -Y.

where
X is any positive integer
WS is erlang:system_info(wordsize)*8*N where N is 1 or larger
Y is any positive integer smaller than (1 bsl WS)

Fix:
The subtraction of 1 (for 2-complement conversion)
must be carried along all the way to the last words.

We only do this when the user has explicitly told us it's okay to
partially disable mitigation (spectre-mitigation=incomplete). The
macro is inert if it isn't.

Note that the ERTS_NO_RETPOLINE macro introduced by this commit is
completely inert unless spectre-mitigation is set to 'incomplete.'
This includes when mitigation has been manually enabled through
CFLAGS, so it should be impossible for it to unintentionally
disable mitigation.

* hans/eldap/prevent_EXIT_at_close/OTP-15342/ERIERL-242:
  eldap: Fix race at socket close