[meson] Pass cpp_eh=none and cpp_rtti=false as default options If we want to support a build with exception handling and RTTI We should reflect that on library(..., link_language: 'c') also so for now it is ok to just set it here to get MSVC support also and we can remove hard coded flags later upon request. One other concern over just relying on it is on when harfbuzz is used as a subproject and the parent project hasn't provided the same options, that should be resolved first I think. Closes #2584