macOS build support

[curiousercreative]

Although not all Mac hardware or macOS versions can run ccminer, it runs well on a 2009-2012 Mac Pro with High Sierra and Nvidia web drivers installed and we should support it if the effort is minimal.

[djm34]

ok, I will have a look.
Am not sure compilation will work without c++11 flag. This one is required for some vector type (std::deque)
What kind of card are used on mac ? Pascal or Turing ?

[curiousercreative]

@djm34 Pascal. I was able to build and the miner ran overnight stably with a 1080Ti.

[djm34]

ok

[curiousercreative]

@djm34 would this solution be more appropriate? I can try a build with it to verify macOS.

[djm34]

I don't have much time at the moment, but if you can do a pull request, I will have a look into it (and accept it if ok).
Don't use the "install.sh" though. Currently the compilation procedure (and I don't really want to change it, or may-be a install_macos.sh) is ./autogen.sh ; ./configure; make -j (so if you can make it such it works like this it would be great).

I have however a concern, you say it runs well on 2009-2012 Mac Pro... that sounds a bit prehistoric too me.

[curiousercreative]

Pull request: #58

Deleted the INSTALL text file and renamed the build script to build-mac.sh. As for the the old Mac Pro, it's the only Mac that can run high performance NVIDIA GPUs.