Return value is the number of events found. This also propagates to the return value of zmq_poller_wait_all.

zmq_poller_wait was only returning events on the first-registered socket.

avoid passing duplicate entries to zmq_poll

zmq_poller doesn't allow a socket to appear twice

heap-allocate events in zmq_poller_poll

variable-size array allocation is not allowed by some compilers

Support all sockets in zmq_poll

only define clock macros on darwin if not already defined

update socket_poller when ZMQ_POLL_BASED_ON_SELECT

enables zmq_poll on threadsafe sockets only supported in zmq_poller (radio, dish, etc.)

previous patch updated only the branch for ZMQ_POLL_BASED_ON_POLL, causing failed builds on Windows.

clang from Xcode 8 has these already defined, causing duplicate macro warnings

Problem: Brocade has copyright but not in AUTHORS and RELICENSE

Problem: pkg-config Requires.private is broken

Solution: add it. Some of the work that I do happens during working
hours and hence the copyright belongs to my employer, Brocade
Communications Systems Inc. Note this in the AUTHORS file.

Solution: use only Libs.private to avoid breaking application builds.
Even though Requires.private are supposed to be parsed only if
pkg-config is called with --static, the --cflags parameter is enough
to trigger the parsing, causing build failures for applications that
do not (and should not) depend on libzmq's dependencies.

Problem: pkgconfig file does not support static link

Solution: add dependencies, if necessary, to the .private Libs and
Requires field of the pkgconfig file at build time.
This way pkg-config --static --libs libzmq will correctly print
dependencies if they were used to build the static libzmq.a library.

pass through poller events

instead of allocating a new, identical array and copying the data.

This is only safe while zmq_poller_event_t and zmq::socket_poller_t::event_t are the same struct,
which they presumably will remain.

add n_events argument to zmq_poller_wait_all

avoids unnecessary heap allocations, races on the number of items

Problem: zmq_poller only signals one event

Solution: zmq_poller_wait_all signals all events

allows signaling multiple events with one call to zmq_poller_wait_all
rather than emitting only one event.

this prepares for zmq_poll being based on zmq_poller,
which requires events for all sockets rather than just one.

* fix bugs of the pollset

1. extend 'fd_table' when fd_ is greater or equal than the size of 'fd_table';
2. delete specific fd from pollset before reset pollin or pollout according the description of AIX document

* fix bugs of the pollset

edit error. remove extra spaces and paste fault

* fix bugs of pollset

remove character '-' at the end line.

fix markup syntax on zmq_tipc(7) page

Fix fd_entry may reference invalid object.

fd_entries (std::vector) can reallocate underlying storage
which will render reference invalid.

Problem: zmq_ctx_term asserts with connect-before-bind and sockets with identity over inproc transport

Solution: add a zmq_assert to check if the ephemeral sockets created
to drain the queue of pending inproc connecting sockets was allocated
successfully.

Problem: zmq_ctx_term asserts with connect-before-bind and sockets with identity over inproc transport

Solution: check if the connecting inproc socket has been closed
before trying to send the identity.
Otherwise the pipe will be in waiting_for_delimiter state causing
writes to fail and the connect to assert when the context is being
torn down and the pending inproc connects are resolved.
Add test case that covers this behaviour.

Solution: add one to increase coverage

Problem: Pub socket crashes on client disconnect. 

Problem: Pub socket crashes on client disconnect.  family_entry.fd_entries [i] is modified in zmq::select_t::rm_fd()
Solution: do not copy family_entry.fd_entries [i]

Problem: documentation markup unrecognized

The effect can be seen on http://api.zeromq.org/4-2:zmq-getsockopt at
options ZMQ_USE_FD and ZMQ_RATE.

Solution: fix length of squiggly line under option title

Pollset-change the position of `pollset`