fcm make: build: basic Fortran OMP dependency

Detect `!$ ` in front of `use` and `include` statements. Recognise them
as dependencies if `build.prop{fc.flag-omp}` is set. Filter them out
otherwise.
t/fcm-make/23-build-omp.t: loops to one-liners

The one-liners are more efficient and easier to read than the loops.
Merge pull request #114 from matthewrmshin/omp

fcm make: build: basic Fortran OMP dependency