Contains a list of directories used by gmake to determine the list of source files to build. All source files listed by the filename expansion expressions *.F90, *.F, and *.c in each of the directories are included in the build. It a given filename occurs in more than one of the directories, it is the version in the first directory of the list that will be built. The list of directories in Filepath will vary with target architecture and depend on the specified dynamics and physics packages.