Remove (HD)off_t from the H5Pset/get_external calls

[derobins]

Supporting off_t is a pain on Windows and is only used in one
pair of public API calls, where it's semantically odd because
negative values aren't allowed.

This PR removes off_t and replaces it with uint64_t.

• Remove off_t from H5Pset/get_external() calls
• Remove off_t from set/getExternal() C++ calls
• Remove off_t from the Fortran interface
• Remove OFF_T as a Fortran INTEGER KIND

Internally, HDoff_t remains in a few places where it's used
in POSIX I/O calls.

---

Important

Replace off_t with uint64_t in HDF5 external file interfaces for better Windows compatibility.

• Behavior:
  • Replace off_t with uint64_t in H5Pset_external() and H5Pget_external() in H5Pdcpl.c and H5Ppublic.h.
  • Update C++ methods setExternal() and getExternal() in H5DcreatProp.cpp and H5DcreatProp.h to use uint64_t.
  • Modify Fortran interfaces h5pset_external_c() and h5pget_external_c() in H5Pf.c and H5Pff.F90 to use uint64_t_f.
• Fortran:
  • Remove OFF_T as a Fortran INTEGER KIND in H5match_types.c.
• Java:
  • Change offset parameter to uint64_t in h5pDCPLImp.c.
• Documentation:
  • Update RELEASE.txt to reflect changes in offset parameter types and removal of OFF_T.
• Misc:
  • Internal HDoff_t usage remains for POSIX I/O calls in H5Defl.c and H5FDstdio.c.

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[derobins]

This PR replaces #5082, which was wildly out of date.

[brtnfld]

I would remove the C wrappers for Fortran and call the C API directly, as long as we are doing updates anyway. I can do that later if you'd like.

[derobins]

I would remove the C wrappers for Fortran and call the C API directly, as long as we are doing updates anyway. I can do that later if you'd like.

I'll update it tonight.

[jhendersonHDF]

Accidentally approved; We decided that for consistency it would be a good idea to version H5Pset/get_external. @derobins could you do this?

[derobins]

Accidentally approved; We decided that for consistency it would be a good idea to version H5Pset/get_external. @derobins could you do this?

I can but it'll take more time. I'll have to write tests, etc.

[jhendersonHDF]

Closing this for now, as we'll need to revisit during the next major release. #6257 created to keep track of it.