Alembic: remove support for HDF5 archive format

Alembic is not a single file format, it can be stored in two different
ways: Ogawa and HDF5. Ogawa replaced HDF5 and is smaller and much faster
(4-25x) to read ([source](http://exocortex.com/blog/alembic_is_about_to_get_really_fast)).

As long as Blender has had Alembic support, it has never supported the
HDF5 format in any release. There is a build option `WITH_ALEMBIC_HDF5`
that can be used to enable HDF5 support in your own build. This commit
removes this build option and the code that it manages.

In the years that I have been maintainer of Blender's Alembic code, I
only remember getting a request to support HDF5 once, and that was to
support very old software that has likely since then been updated to
support Ogawa. Ubuntu and Fedora also seem to bundle Blender without
HDF5 support.

This decision was discussed on
[DevTalk](https://devtalk.blender.org/t/alembic-hdf5-support-completely-remove)
where someone also mentioned that there is a tool available that can
convert HDF5 files to the Ogawa format.

1 files changed, 0 insertions, 1 deletions

diff --git a/source/blender/makesrna/RNA_enum_types.h b/source/blender/makesrna/RNA_enum_types.h
index b6bae805636..0c462ba6766 100644
--- a/source/blender/makesrna/RNA_enum_types.h
+++ b/source/blender/makesrna/RNA_enum_types.h
@@ -225,7 +225,6 @@ extern const EnumPropertyItem rna_enum_dt_mix_mode_items[];
 extern const EnumPropertyItem rna_enum_dt_layers_select_src_items[];
 extern const EnumPropertyItem rna_enum_dt_layers_select_dst_items[];
 
-extern const EnumPropertyItem rna_enum_abc_compression_items[];
 extern const EnumPropertyItem rna_enum_context_mode_items[];
 
 extern const EnumPropertyItem rna_enum_curveprofile_preset_items[];