graphite2 gcc-15+ FTBFS tracking

[John Chittum]

Bug to track gcc-15+ issues with graphite2.

Upstream bug: https://github.com/silnrsi/graphite/issues/96

This relates to https://bugs.launchpad.net/ubuntu/+source/graphite2/+bug/2124952

and

bugs.launchpad.net/ubuntu/+source/graphite2/+bug/2120856

graphite2 fails to build on gcc-15+ on arm64, ppc64el, s390x, amdv3. There are further build issues during autopkgtest where 03 is not being stripped in the same way as it is during the package builds.

To solve those 2 bugs at least for resolute (and further), we've shifted everything to building with gcc-14. This solves immediate build issues, but there will need to be a heavier lift in the future as toolchains progress.