RELICENSE: Christoph Schulz

CMake cleanup

- Lowercase all commands
- Unify indent to 2 spaces
- Remove spaces around brackets
- Remove repitition of condition in else(...) and endif(...)

Note: (re-)running CMake did not change the content of the generated files

RELICENSE: Byron Mallett

Added relicensing permission from Byron Mallett

Solution: fix them

* Added SO_REUSEPORT socket option for UDP multicast recv ports

Revert "Problem: test_proxy not yet using unity"

This reverts commit fd27324e.

Migrate tests to unity, reduce duplication

Solution: migrate to unity

Solution: merge into a single test_use_fd and reduce code duplication by extracting common functions

Solution: migrate to unity

Solution: migrate to unity

Solution: migrate to unity

Solution: migrate to unity

Solution: migrate to unity

Fix build failure on ARM due to bad variable name

The variable decrement was changed to decrement_
in c581f43c

In -one- place, it remained as decrement
and gives:

In file included from src/ctx.hpp:44:0,
from src/address.cpp:33:
src/atomic_counter.hpp: In member function 'bool zmq::atomic_counter_t::sub(zmq::atomic_counter_t::integer_t)':
src/atomic_counter.hpp:191:28: error: 'decrement' was not declared in this scope

Changing it to decrement_ fixes the problem.

Migrate further tests to unity

Solution: use utilities from testutil_unity, reduce duplication

Solution: migrate to unity

Solution: migrate to unity

Solution: migrate to unity

Solution: extracted into common method

Solution: migrate to unity

Solution: migrate to unity

Solution: migrate to unity

Solution: migrate to unity

Solution: migrate to unity

Solution: migrate to unity

Solution: fix it to comply with clang-format rules

* Relicensing grant by Ming Ji <jiming@yafco.com>

Permission to relicense under any OSI approved license chosen by the current ZeroMQ BDFL.

Solution: migrate to unity

Solution: fix them

Problem: PGM receiver can crash due to race

Solution: do not run in_event until restart_input finishes correctly.
Signed-off-by: answeroo <jiming@yafco.com>

Problem: inconsistent _out_pipes when using the same routing id witho…

Solution: added test case, do not erase existing without ZMQ_ROUTER_HANDOVER