F_name_impl with fortran_generic

Using the F_name_impl format string to explicitly name a Fortran wrapper combined with the fortran_generic field may present some surprising behavior. The routine BA_change takes a long argument. However, this is inconvenient in Fortran since the default integer is typically an int. When passing a constant you need to explicitly state the kind as 0_C_LONG. Shroud lets you create a generic routine which will also accept 0. But if you explicitly name the function using F_name_impl, both Fortran generated functions will have the same name. The solution is to set format field F_name_generic and the option for F_name_impl_template.

- decl: int BA_change(const char *name, long n)
    F_name_generic: change
    F_name_impl_template: "{F_name_generic}{function_suffix}"
  - decl: (int n)
    function_suffix: int
  - decl: (long n)
    function_suffix: long

Will generate the Fortran code

interface change
    module procedure change_int
    module procedure change_long
end interface change