CPP out LOC calls for NAG.

[DJDavies2]

Resolves #62. The LOC intrinsic is only used for some write statements, so it looks like it can be cpp'ed out for NAG. I can do something more sophisticated if desired, but this change results in this ecbuild output:

-- Checking Fortran support for "finalization"
-- Checking Fortran support for "finalization" -- works
-- Feature FINAL enabled
-- FCKIT_HAVE_FINAL [1]
-- FCKIT_FINAL_FUNCTION_RESULT = 1
-- FCKIT_FINAL_UNINITIALIZED_LOCAL = 0
-- FCKIT_FINAL_UNINITIALIZED_INTENT_OUT = 1
-- FCKIT_FINAL_UNINITIALIZED_INTENT_INOUT = 0
-- FCKIT_FINAL_NOT_PROPAGATING = 0
-- FCKIT_FINAL_NOT_INHERITING = 0
-- FCKIT_FINAL_BROKEN_FOR_ALLOCATABLE_ARRAY = 0
-- FCKIT_FINAL_BROKEN_FOR_AUTOMATIC_ARRAY = 0