Solution: mention new version of wepoll and Android Things fix

Solution: fix them

Problem: compiler might not support atomic warning flag

Solution: check before using it

* include atomic when needed

* update for tipc

* moved check under android

* added license

Problem: wepoll 1.5.2 is outdated

Solution: Update to upstream version 1.5.4

Problems: no example for STATISTICS proxy command, no getters for some context options, new events zmq_stopwatch_intermediate proxy STATISTICS and context thread options are eligible to be made STABLE

Solution: do it

Solution: add it

Solution: do it

Solution: add one so that class-based bindings can easily use them

Solution: do it

Solution: do it

Problem: radix tree never used in autotools builds

Solution: add a switch and a default to autoconf

* Add specific option to select radix tree implementation for subscriptions (defaults to ON if draft API enabled).

Problems: some tests still use hard-coded TCP ports, wrong usage of CPPFLAGS, missing NEWS, no way to force C++98 builds and CI for it

Problem: C4 process is not easily discoverable.

Solution: Add a relicensing grant.

Solution: Add 'Contributing' section to README.md

Solution: cast the unused variable

Solution: if the compiler supports it, pass C++98-compat flags.
Currently Clang supports this flag but GCC does not.

Add a new flag to enable it, as building with C++98-compat but also
with -std=gnu++11 will cause a lot of warnings due to the backward
compat ifdefs.

Add a CI job to run it and ensure we don't break compatibility.

Solution: use CXXFLAGS for compiler flags and CPPFLAGS for preprocessor
flags.

Solution: add it

Solution: do not bind to an hard-coded port, use a wildcard.

Solution: do not bind to an hard-coded port, use a wildcard.

Solution: add them to .gitignore

* Problem: radix tree needs benchmarks and improvements

Solution: add a benchmark and make suggested improvements

Problem: #3263 not mentioned in NEWS

Solution: add it

Problem: using FD_SETSIZE for optimized_fd_set_t is a pessimization

Reapply session_base_t refactoring

Solution: do not use make_pair

Windows apparently returns `WSAENOBUFS` from `recv`

Problem: Assert being triggered when Windows returns `WSAENOBUFS` from `recv` call on large buffers.

Solution: Expect `WSAENOBUFS` as a valid response.  See https://github.com/zeromq/libzmq/issues/3263

Solution: added relicense agreement

Solution: extract functions for each protocol

Problem: build broken with Sun Studio, tests fail on debian/kfreebsd and debian/hurd, DRAFT zmq_poll is slow