compiled with the fortran compiler. Any .h, .hh, .hpp, or .hxx files will
not be compiled separately, but, if these header files are changed,
the package (including its non-Go source files) will be recompiled.
Note that changes to files in other directories do not cause the package
to be recompiled, so all non-Go source code for the package should be
stored in the package directory, not in subdirectories.