The build system now passes compiler directives based on the mode being build. By default data is stored in the source root (and this is encoded into the compiled binary). However, if building in user mode then data is assumed to be at the meson install prefix data directory
MFEM is a dependency of our code and we want to build it with our code for portability, here I add a meson subproject which fetches mfem and builds it. Because of some issues with CMake and meson I apply a patch which manually disables running tests and building examples and miniapps in mfem. This is okay as mfem here is not intenteded to be linked against other programs (though it still can be).
we will use meson as the build system for this project. Added a rough outline of this which builds source, libraries, and links them to tests (along with the google test library for testing). meson will be setup and compiled with ./mk.
