Gyp needs its own platform.hpp; there is no way to delete this
file automatically.
Solution: copy gyp's platform.hpp into src, so that things build
properly no matter what the starting state. If you build with gyp
and then try to build using autotools' makefile, you'll get an
error from the platform.hpp.
This is rather insane since the code knows well enough what systems
support if_nametoindex. I blame this on over-use of autotools early
in libzmq's days.
Anyhow, this breaks gyp builds on OS/X.
Solution: add ZMQ_HAVE_IFADDRS to build/gyp/platform.hpp for OS/X.
I'm adding gyp support so that we can easily pull in libzmq
and other C/C++ projects into gyp packages, especially via
node-gyp.
Solution: add gyp definition
This works only for Windows, OS/X, and Linux. We set a single
macro in project.gyp according to the system, and the rest is
done in builds/gyp/platform.hpp. The values in that file are
not dynamic. Your mileage will vary.
