buildhistory.bbclass: support extending the content of the build history
The idea behind the implementation of Yocto #8138 was that an
additional class can write additional files in the recipe directories,
for example by hooking into the functions of buildhistory.bbclass or
by implementing its own SSTATEPOSTINSTFUNCS function.
However, when these additional files get created before
buildhistory_emit_pkghistory(), they get removed again by that
function because it contains code which removes everything it does
not know about. The reason for that is that these unknown items
are probably obsolete.
This logic is the reason why the additional "kconfig" file from
buildhistory-extra.bbclass never showed up in the final build history.
To fix this, the hard-coded list of known files in
buildhistory_emit_pkghistory() must be turned into a variable which
derived classes can extend.
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
