FindOpenMP: Language-specific components
This MR adds components to FindOpenMP
akin to the components model in !893 (merged) for MPI. OpenMP_FOUND
is defined to be true if all requested languages are found and OpenMP_VERSION
is the overall minimum among enabled components.
Side note: I've also folded a commit in this MR that adds the specification date of the 5.0 preview 1 to the version map, since Intel 18.0 compilers define this now.