Add transport_opt() watchdog_config

To make the number of watchdogs sent before the transitions REOPEN ->
OKAY and OKAY -> SUSPECT configurable. Using anything other then the
default config is non-standard and should only be used for test.
Minor spec fix
Rework stats to avoid concurrent read and write

Counters read by diameter:service_info(SvcName, transport) can be
selected at the same time as the diameter_stats server is folding them
into another key, possibly resulting in inaccurate values. Have
diameter_stats select from the server process to avoid this and add
diameter_stats:sum/1 to sum values from all contributors on a given
term.
Rework watchdog suite to remove most timing dependencies

Count watchdog messages instead when this is an alternative.
Add testcases for watchdog_config
Tweak okay -> suspect config

Make it just a number of timeouts, without a new DWR being sent.
Removed timing rekeying
Distribution fixes

This is the functionality that allows transports to be shared between
identically-named services on different nodes, which has been neither
documented nor tested (until now).
Document distribution config
Add distribution suite
More flexible distribution config

Allow both share_peers and use_shared_peers to be a list of nodes, or a
function that returns a list of nodes.
Specify timeouts to ct_slave:start/2
Fix SSL Next Protocol Negotiation documentation

Fix inconsistencies
Fix typos
Fix data types definition
Set unique anchor on +pc flag in erl.xml
Merge branch 'pan/wrong_anchor_in_erl.xml' into maint

* pan/wrong_anchor_in_erl.xml:
  Set unique anchor on +pc flag in erl.xml

OTP-10947
Make configure test for fallocate try to link

This hopefully detects fault glibc's where
fallocate64 is nonexistent.
Merge branch 'pan/fallocate_stricter_autoconf' into maint

* pan/fallocate_stricter_autoconf:
  Make configure test for fallocate try to link

OTP-10948
Add dependency to dtrace header for parallell make
Merge branch 'pan/dtrace_header_dependency' into maint

* pan/dtrace_header_dependency:
  Add dependency to dtrace header for parallell make

OTP-10949
inets httpc: Revert incorrect commit regarding cookie handling.