Install relocatable dylibs (MacOS)

Problem: When building libzmq with CMake, the installed libzmq.dylib
  has a relative install name (otool -D libzmq.dylib) on MacOS. This
  is a regression against building via autotools which sets an
  absolute install name. Effectively, the CMake built libzmq.dylib
  is rendered useless if installed in non-system directories and
  used in environments without explicit DYLD_LIBRARY_PATH mgmt. For
  example running any of the installed executables currently fails:
  $ /some_install_prefix/bin/inproc_lat
  dyld: Library not loaded: libzmq.5.dylib
    Referenced from: /some_install_prefix/bin/inproc_lat
    Reason: image not found
  Trace/BPT trap: 5

Solution: Best practice is to install relocatable dylibs.
  On MacOS this means setting an install name with a special prefix,
  e.g. @rpath/libzmq.dylib, and adding the relevant search paths
  to the embedded rpath list. In this patch the necessary CMake options
  are added to generate the desired relocatable dylibs. Find more
  information on: https://cmake.org/Wiki/CMake_RPATH_handling.

Problem: Server-client not marked as DRAFT in manpage

Solution: add note like for radio-dish
Fixes: #3050

Fix fd_t variable casting on Windows platform

event_accepted() already accepts fd_t type and there is no reason to cast it to int type
Moreover, on Windows x64 this leads to truncation memsize -> int

configure.ac: serach for dladdr only on libunwind

The original configure.ac tries to check for dladdr, but it actually needs
it only in case we have libunwind (which has a another section and checks for it
too).
This can fail the build on systems without dynamic linking support.
Therefore, the dladdr check has to be preformed only when checking libunwind.
Signed-off-by: Asaf Kahlon <asafka7@gmail.com>

* Implement the wsa_error_no function with switch-case
Signed-off-by: Asaf Kahlon <asafka7@gmail.com>

* Fixes issues with the PDB install rule for VS solutions

* Fix for compile PDB and linker PDB under Windows

Problem: C++ style comments in header file breaks pedantic build

Solution: change missing comments in header file
Fixes: #3036 and adds on top of '15905c55'

Problem: C++ style comments in C file breaks pedantic build

Solution: change comments
Fixes: #3036

Fix assertion failure when calling zmq_poller_destroy after zmq_ctx_term

Problem: socket_poller destruction after context shutdown is only tested with a non-thread-safe socket

Solution: test with both thread-safe and non-thread-safe sockets

Solution: do not call getsockopt to query thread-safety of a socket

Solution: Added test case to reproduce, not solving the problem!

Problem: clang-format Travis job broken

Solution: don't run configure

* always run tests from tarball of `make dist`

ensures that tests will not pass if critical files are omitted from releases

* add explicit make dist only for non-default builds

distcheck should already cover this for default builds

* don’t verify that valgrind/coverage tests can be run from dists

* add various files missing from dists

- missing template from cmake
- add missing android build files
- add some missing ci_build.sh scripts

Problem: 4.2.5 is out, we need to restore API changes and 4.3.x

Solution: revert the revert!

Revert "Problem: regression in 4.2.3 went unnoticed, want to release 4.2.5"

This reverts commit 5f17e26f.

Problem: regression in 4.2.3 needs to be fixed before 4.3

Solution: note bug fixes

Solution: revert DRAFT -> STABLE API transition so that we can do a
bugfix-only 4.2.5 release.
Will be re-reverted once tagged.

Revert "Problem: ZMQ_BINDTODEVICE has met STABLE conditions"

This reverts commit 3cb79f50.

Revert "Problem: ZMQ_MSG_GSSAPI_* have met STABLE conditions"

This reverts commit 374da420.

Revert "Problem: ZMQ_MSG_T_SIZE has met STABLE conditions"

This reverts commit 6411c4a2.

Revert "Problem: docs say STABLE API still in DRAFT"

This reverts commit 9f2f30b7.

Problem: backward incompatible change to NULL with ZAP

Solution: like for other mechanism, do not enforce strict ZAP protocol
adherence unless the specific socket option is enabled with NULL auth.

Add test to exercise this functionality, and fix ZAP test to set the
socket option when it uses NULL auth.

See: https://github.com/zeromq/pyzmq/pull/1152

Solution: override unused parameter for NULL wrapper

Problem: some inaccuracies in manpages

Solution: fix it, as since 4.2.0 there is no ordering constraint
anymore
Fixes: #2854

Solution: clarify it since it's a common source of confusion

Solution: update them

Fix gcc build problem

Fixed gcc-related build problem resulting from `-errwarn=%all` switch.

Fixes #3012.

Problems: some APIs have met stable conditions

Solution: move them from DRAFT to STABLE since it's been in a public
release, committed for 6+ months and has not changed.

Solution: move them from DRAFT to STABLE since it's been in a public
release, committed for 6+ months and has not changed.

Solution: update manpages