- devel package obsoletes and provides ilmbase-devel

- run spec-cleaner

- fix baselibs.conf
- modified sources
% baselibs.conf

- version update to 3.1.1
3.1.1
* Patch release that fixes build failures on various systems,
introduces CMake CMAKE_CROSSCOMPILING_EMULATOR support, and
fixes a few other minor issues.
3.1
* The 3.1 release of OpenEXR introduces a new library, OpenEXRCore,
which is the result of a significant re-thinking of how OpenEXR
manages file I/O and provides access to image data. It begins
to address long-standing scalability issues with multithreaded
image reading and writing.
3.0.1
Major release with major build restructing, security improvements, and
new features:
* Restructuring:
- The IlmBase/PyIlmBase submodules have been separated into the
Imath project, now included by OpenEXR via a CMake submodule
dependency, fetched automatically via CMake's FetchContent if
necessary.
- The library is now called ``libOpenEXR`` (instead of
``libIlmImf``). No header files have been renamed, they retain
the ``Imf`` prefix.