Caused by error in last commit which used HAVE_LIBSODIUM instead
of HAVE_SODIUM.

Solution: use HAVE_LIBSODIUM as we do in other configure scripts.

The project is called 'libsodium' and not 'sodium'.

There is an option to enable/disable libsodium via the Visual Studio
UI. This is not practical for command-line usage (via msbuild).

Solution: add configure.bat that searches for libsodium in sibling
directory to libzmq; if it finds it, defines HAVE_LIBSODIUM 1.

This is consistent with zproject, which has the same problem and
is getting the same solution for all dependency resolution on
Windows.

Note that this approach also provides a way to support tweetnacl
via a configure option.

Also, removed duplicate props files and re-copy in configure.bat
as it was an insane nightmare to update these by hand. (and not
clear that they were identical. Now it's forced.)

Solution: fix .gitignore

Make VMCI work on Windows

configure doesn't correctly determine mingw64

select was improved to support multiple service providers on Windows.
it should be slightly faster because of optimized iteration
over selected sockets.

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.

conformity update for mingw32 variables to mingw

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

Fixed VS2015 build

Leading to extra work when copying between versions of VS.

Solution: remove second unnecessary definition.

Solution: add missing project files

(Also, updated FD_SETSIZE to 16K as a bonus.)

Problem: not building on VS2015

Solution: fixed project files, and warning in timers.cpp

Revert "Revert "Problem: deprecated use and reference of `zmq_term`""

Revert "Problem: deprecated use and reference of `zmq_term`"

Problem: deprecated use and reference of `zmq_term`

Solution: Replace with `zmq_ctx_term`

Solution: replace with `zmq_ctx_term`

Also fix whitespace (tabs instead of spaces)

Solution: replace all occurrences with `zmq_ctx_term`

Solution: replace all occurrences with `zmq_ctx_term`

fixed issue #1754

Problem: deprecated `zmq_utils.h` is still included

Solution: remove all remaining references to `zmq_utils.h`

Problem: various errors in build scripts

- zmq_utils.h was removed
- udp_address.cpp and udp_engine.cpp were added

Solution: patch all affected build scripts

Added "udp_address" and "udp_engine" to VS2015 project

I hope restoring this from a previous version doesn't do any damage, it
is missing in the current version of this repository and is vital for
the lib to compile anywhere.

Altered VS2015 files to enable building of the library.

Problem: `zmq_utils.h` is deprecated since 2014-07-09

Solution: remove this file

Since they are allowed

(They are not, however, allowed in hostnames)

Fix unused-parameter/unused-but-set-variable/missing-field-initializers warnings