Package library

[denniskb]

Clean up cmake, make experience smooth. Potentially replace scripts with cmake add_subdirectory.

[denniskb]

Check invariants for now, while the app is still in alpha, to help catch bugs..

[denniskb]

@oikonom stuff to do:

• Replace third party build script with CMake's add_subdirectory. This requires figuring out how to pass options down to subprojects first (without polluting our own options/flags). Some links that might be helpful:
  • https://cmake.org/pipermail/cmake/2016-May/063469.html
  • https://stackoverflow.com/questions/14061605/override-option-in-cmake-subproject
  • https://stackoverflow.com/questions/20239334/cmake-set-subdirectory-options
• Split out master CMakeLists.txt file into per-project files (one for spice, test, bench, and all the samples). Make sure to keep all our options inside the master file however, so users of our library can see what build configurations we offer at a glance.
• Replace file GLOBing with explicit file lists.
• Split spice/ into include/ and src/. The current spice/ folder should become the first and only child of the new include/ folder with all the source files extracted into the src/ folder. The src/ folder should mirror the structure of the include/ folder. The idea is that installing spice headers is as simple as copy-pasting the include/ folder.
• See if linking against pthreads from within spice with the PUBLIC options absolves us from the need to link against pthreads inside test/bench/samples.
• Turn on "spice_assert_invariants" by default.

[denniskb]

Please do your changes inside branch "issue/5" so we maintain a mapping between branches and github issues.

[denniskb]

@oikonom I re-worked the entire build experience. Let me know if it works now. Try out both raw CMake and the vscode tasks if you can. The scripts configure.sh and build.sh should not be used directly by users.