build.sh: always set SOURCE_DATE_EPOCH if unset or set but null -- default to lastest git commit timestamp or date +%s

set SOURCE_DATE_EPOCH based on last git commit and use it for d/changelog and embed it in the kernel version

add ecspi entry for lpc

See merge request !2

temporarily remove ffmpeg as the patch no longer works with 5.x

See merge request !3

currently, building blender fails to builds with:

    In file included from /usr/include/openvdb/tools/LevelSetRebuild.h:11,
                     from /usr/include/openvdb/tools/GridTransformer.h:16,
                     from /usr/include/openvdb/tools/Clip.h:16,
                     from /<<PKGBUILDDIR>>/intern/openvdb/intern/openvdb_dense_convert.h:34,
                     from /<<PKGBUILDDIR>>/intern/openvdb/openvdb_capi.cc:27:
    /usr/include/openvdb/tools/VolumeToMesh.h:21:10: fatal error: tbb/task_scheduler_init.h: No such file or directory
       21 | #include <tbb/task_scheduler_init.h>
          |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~
    compilation terminated.

This is because tbb dropped the tbb/task_scheduler_init.h header. Fixing this
has to happen in openvdb but the proper fix will be to add support for onetbb
to openvdb because tbb developers changed the name to onetbb:
https://github.com/oneapi-src/oneTBB
Tracking bug in Debian:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1011215
OpenVDB bug:
https://github.com/AcademySoftwareFoundation/openvdb/issues/1366

https://github.com/ftrvxmtrx/void-packages/commit/52f060dfcc424177809a39d350617344f5d202ba

blender currently fails to build with:

    ./source/blender/imbuf/intern/oiio/openimageio_api.cpp:246: error: undefined reference to 'OpenImageIO_v2_3::TypeDesc::basesize() const'
    /usr/include/OpenImageIO/paramlist.h:107: error: undefined reference to 'OpenImageIO_v2_3::ParamValue::clear_value()'
    /usr/include/OpenImageIO/paramlist.h:107: error: undefined reference to 'OpenImageIO_v2_3::ParamValue::clear_value()'
    /usr/include/OpenImageIO/paramlist.h:107: error: undefined reference to 'OpenImageIO_v2_3::ParamValue::clear_value()'
    collect2: error: ld returned 1 exit status

This reverts commit f2e88e29.

https://bugs.debian.org/1009858