- Configure external timezone database provided by the timezone
package. Make libstdc++6 recommend timezone to get a fully
working std::chrono. Install timezone when running the testsuite.
- Remove dependence on doxygen and graphviz when building the
testsuite. Those were used to build the libstdc++ API html
documentation but we stopped shipping that when Java support
was removed and nobody noticed. Purge traces of the built
libstdc++6-gccN-doc package.
- Package libhwasan_preinit.o on x86_64.

- Update to GCC trunk head (r13-5199-g2f81164255bf0d)
* pulls changes up to the start of Stage 4
- Change version numbering to match the commit count from
the git gcc-descr alias
- Add gcc13-pr107678.patch to fix unwinding on aarch64 with
pointer signing. [bsc#1206684]

- Don't rely on %usrmerged, set it based on standard %suse_version

- Enable PRU flavour for gcc13