Add support for linux (using Cmake)

[ssj71]

I added support for building the plugins in Linux using cmake. There is a little documentation in the CMakeLists.txt file in source. It probably could be made to use cmake for all platforms, but since you already have ways to do it on windows/mac I just got it working for linux.

There is also a tiny change in the source (adding an include to avoid errors about snprintf).

Cool project, thanks for sharing the code!

[kmturley]

There seems to be some comments on how to build the linux version here:
https://www.kvraudio.com/forum/viewtopic.php?p=6774133&sid=acbd59f0d3aff2c976b007a8e15fefe3#p6774133

You can also use Docker Compose to run the CMake files:

version: '3'
services:

  linux:
    image: ubuntu
    ports:
      - "8080:8080"
    volumes:
      - .:/usr/src/app

Then run:

docker-compose run linux
apt-get update
apt-get install cmake gcc build-essential "libstdc++6" libx11-xcb-dev libxcb-util-dev libxcb-cursor-dev libxcb-xkb-dev libxkbcommon-dev libxkbcommon-x11-dev libfontconfig1-dev libcairo2-dev libgtkmm-3.0-dev libsqlite3-dev libxcb-keysyms1-dev libasound2-dev
cd /usr/src/app/build
cmake ../source/
make