Commit 2ec5a33f added support to link
with -latomic if needed however using LDFLAGS doesn't work when
statically linking because LDFLAGS is added before LIBS

Detection of atomic fails with:

configure:23230: /accts/mlweber1/instance-2/output/host/bin/sparc-linux-g++ -o conftest -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os   -static -static -pedantic -Werror -Wall -D_GNU_SOURCE -D_REENTRANT -D_THREAD_SAFE -Wno-long-long -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -static -latomic conftest.cpp -lrt -lpthread -lstdc++ >&5
/tmp/ccgrvVTg.o: In function `main':
conftest.cpp:(.text.startup+0x10): undefined reference to `__atomic_fetch_add_4'
collect2: error: ld returned 1 exit status

So use LIBS instead of LDFLAGS

Fixes:
 - http://autobuild.buildroot.net/results/c471d6b1061a8516f7772735e471db68a32965aaSigned-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

Solution: add wepoll as a polling system

Problem: API poller cannot be set independently from I/O thread poller, poll I/O thread poller broken on Windows

Solution: change platform definitions to separate API poller from I/O thread poller, disallow configuring poll I/O thread poller on Windows

Solution: check return value in autoconf and CMake. On some platforms
the function is available but not implemented (eg: GNU/Hurd).

On some cases, -latomic is needed for likning, and since the current
acinclude.m4 checks only compilation we can sometimes miss the need for -latomic
and the linking process will fail.
Therefore, the AC_CHECK_IFELSE was replaced with AC_LINK_IFELSE. If the first
try fails, we try to link again with -latomic and add LIBS="-latmoic" in case we
succeeded.
Signed-off-by: Asaf Kahlon <asafka7@gmail.com>

Linux now supports Virtual Routing and Forwarding (VRF) as per:

https://www.kernel.org/doc/Documentation/networking/vrf.txt

In order for an application to bind or connect to a socket with an
address in a VRF, they need to first bind the socket to the VRF device:

    setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, dev, strlen(dev)+1);

Note "dev" is the VRF device, eg. VRF "blue", rather than an interface
enslaved to the VRF.

Add a new socket option, ZMQ_BINDTODEVICE, to bind a socket to a device.
In general, if a socket is bound to a device, eg. an interface, only
packets received from that particular device are processed by the socket.

If device is a VRF device, then subsequent binds/connects to that socket
use addresses in the VRF routing table.

Solution: if available use the getrandom function as it doesn't
require any synchronization, state or cleanup

Solution: open with O_CLOEXEC if available or set FD_CLOEXEC if not

(msys building is buggy, please be aware, it fails to compile on my
machine) also I modified the buildall.bat/buildbase.bat to use correct
MSVC versions instead of "visual studio 2017"

Solution: even though epoll() semantics are supported in modern illumos, it may differ from what Linux developers are used to expect. Skip epoll and use poll or select semantics (both were checked to work well).

Solution: if available, use eventfd with EFD_CLOEXEC flag to make
the process close the socket on fork+exec

Solution: if available, use epoll_create1 with EPOLL_CLOEXEC flag to
make the process close the socket on fork+exec

Solution: fix acinclude.m4 snippet that checks if select is
available to stop it erroring out.

Solution: keep the new --without-docs option, but also keep the old
--without-documentation with an added deprecation warning.
We can then remove it in the next major release, to leave enough time
for users and maintainers to change it without disruptions.

add a new poller named pollset which will get benefit of performance in AIX platform.

It's especially annoying to see this:

  --enable-perf           Build performance measurement tools [default=yes].
  --disable-eventfd       disable eventfd [default=no]
  --enable-curve-keygen   Build curve key-generation tool [default=yes].

Solution: all options should explain the non-default case. Also
the language should be enable/disable, with/without, rather than
yes/no. E.g. '--without-docs'.

Specifically, the poller detection code does not set macros in
platform.hpp. The configure script passed them as -D on the command
line.

Solution: rewrite the poller detection code.

changes the search pattern for host_os from *mingw32* to *mingw* so that mingw64 can be used, and any mingw32 variable name change to mingw.

changes the search pattern for host_os from *mingw32* to *mingw* so that mingw64 can be used

It's inconsistent, and should be --with-something=yes/no. Also the
term 'documentation' is long and clumy.

Solution: use --with-docs instead.

Specifically when cross-compiling, one can be willing to force these
variable values using the environment of a config.cache file. This
commit makes this possible.

The affected variables are:

* libzmq_cv_sock_cloexec
* libzmq_cv_so_keepalive
* libzmq_cv_tcp_keepcnt
* libzmq_cv_tcp_keepidle
* libzmq_cv_tcp_keepintvl
* libzmq_cv_tcp_keepalive
Signed-off-by: Lionel Orry <lionel.orry@gmail.com>

Works with GCC and most likely clang

The decision about the poller mechanism to use (select, poll, ...)
was done twice: once by the build system and once by the code in
poller.hpp. As the build-system can actually detect the mechanisms
available, prefer that result to the hard coded defaults in
poller.hpp.

At the same time, remove the duplicate detection of select() vs.
poll()-variant from proxy.cpp, signaler.cpp and zmq.cpp.

This patch has not been tested on many build platforms: especially
the cmake build needs testing / patching. For the other builds,
hard code the result as these these are all Windows platforms.

currently not fully cross-platform
work on linux
possibly work in *bsd
and could be enhanced to work on windows

Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

 - Added a macro for checking clang compiler
 - Moved basic compiler checks to a macro
 - Added a macro for checking if compiler supports a flag
 - Added --enable-debug flag
 - Added a macro for running normal autoconf check with compiler flags
 - Added a macro for checking for verbose flag for different compilers (-Wall)
 - Added a macro for turning on strict standards compliance
 - Added a macro for turning warnings to errors
 - Added a macro for checking if compiler supports given pragma
 - Most of the flags now go through checks if the compilers supports them
   rather than enumerating different compilers
 - Added DSO symbol visibility for sun compiler
 - Enabled verbose mode for sun compiler
 - Fixed build for ICC 12.x by adding -wd279 to size_t checks
 - Removed pkg-config checks as those don't seem to be used anywhere
Signed-off-by: Mikko Koppanen <mkoppanen@php.net>

The patch tests that the C and C++ compilers actually exist
and work. autoconf seems to default to 'g++' when C++ compiler is not
found, which causes the following error (when the compiler isn't
there):

checking for uuid_generate in -luuid... no
configure: error: cannot link with -luuid, install uuid-dev.

The config.log contains the real error message "g++ command not found"
but the error message shown to the user is misleading.
Signed-off-by: Mikko Koppanen <mkoppanen@php.net>