adds build scripts for macOS and Linux

[wschadow]

This add build scripts for Linux and macOS. They are based on the scripts found in SuperSlicer and some options are added:

Usage: ./BuildLinux.sh [-h][-w][-u][-g][-b][-d][-s][-i]
-h: this message
-w: wipe build directories before building
-u: only update dependency packets (optional and need sudo)
-g: force gtk2 build
-b: build in debug mode
-d: build deps
-s: build PrusaSlicer
-i: generate appimage (optional)

[jmickelin]

Hi! Since you mentioned you ported this from SuperSlicer, I just wanted to mention that the build script for the Linux AppImage package at the time of you creating this PR actually contains a bug. It's missing the shared library for STEP-file imports. See here for details: supermerill#3699 (comment)

There is a fix already merged into the nightly_dev branch here, stated to be included in the next version: supermerill@f488430

There doesn't seem to be a corresponding fix for SuperSlicer's MacOS (or Windows) build scripts at the moment. Maybe OCCTWrapper is statically linked on those platforms, so it isn't needed? But @supermerill might also just not have gotten around to it, I'm not sure :)

EDIT: After extracting the DMG of the latest PrusaSlicer release, I can't find any OCCTWrapper .dylib or .so anywhere, so I think it actually might be statically linked. So it's probably safe to ignore that part of my comment in the SuperSlicer repo.

EDIT 2: Oh yes. Indeed: aff3370

[wschadow]

yes, under macOS it is statically linkes. Under Linux there is a change by supermerill which copies the so file die the output bin directory. At least under Debian the library itself is not compiled. This requires an additional change in the CMakeLists.txt.