Fix websocket without path with test

websocket urls without a path caused crash!

problem: ws_engine don't support WS RFC ping-pong and close

Solution: when peer send a close msg, close the connection

Solution: implement both PONG response and producing pings

acinclude.m4: add -latomic to PKGCFG_LIBS_PRIVATE

Add -latomic to PKGCFG_LIBS_PRIVATE so applications linking statically
with libzmq (such czmq) will know that they have to link with -latomic
and the following build failure will be avoided:

  CCLD     src/czmq_selftest
/home/buildroot/autobuild/run/instance-3/output-1/host/opt/ext-toolchain/bin/../lib/gcc/sparc-buildroot-linux-uclibc/7.4.0/../../../../sparc-buildroot-linux-uclibc/bin/ld: /home/buildroot/autobuild/run/instance-3/output-1/host/sparc-buildroot-linux-uclibc/sysroot/usr/lib/libzmq.a(src_libzmq_la-ctx.o): in function `zmq::ctx_t::create_socket(int)':
ctx.cpp:(.text+0x1710): undefined reference to `__atomic_fetch_add_4'

Fixes:
 - http://autobuild.buildroot.org/results/4a12f1ede260cd956a0b5ccb4eec6ca8b44cb04fSigned-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

mingw: add missing namespace

Problems: reimplementation of strlcpy, CMake does not use pkg-config for NSS, wrong pc generated by autoconf with GNUTLS

* Update array.hpp

Problem:Calling back on an empty container causes undefined behavior.
Solution:Check with the function empty()

* Create xqcool.mq

Adds relicensing grant

Solution: check correct preprocessor define in test_reconnect_ivl to match the
test invocation

Solution: initialize local variable in all cases to false positive
compiler warning

Solution: add it to one build to exercise all the code paths

Solution: add it to the Requires.private list

Solution: use pkg-config by default and FindPackage only as a
fallback

Solution: use libbsd by default when available, and the internal implementation
only as a fallback, to take advantage of Linux distros maintenance of the
string libraries.

Avoid possible buffers overruns in ws_engine

Various improvements

Solution: use memcpy with known size instead

Solution: use strcpy_s instead (define custom if not available)

Solution: add static

Solution: removed them

Solution: move initialization to declaration

Solution: modify it in loop body only

Solution: remove the redundant one

Solution: remove them

Solution: just copy the address

Solution: use std::string instead

Solution: properly guard members and options

Solution: use memcpy with known length

Fix set cpu affinity

Solution: Set correct define in CMake check and add the cmakedefine

Fix windows signaler regression

Solution: add comments and remove continue/break

This reverts commit 4f77cfa3.

Make use of = default and = delete if available