Key changes:
- Always use the system alternatives command, although I doubt if this
ever even worked.
- Dropped GTS annobin
- Added the !%have_scl path
Related: RHEL-81741
The bootstrap gcc-toolset-15-binutils doesn't appear to be usable since
it fails to install with the following error:
nothing provides /opt/rh/gcc-toolset-15/root/usr/sbin/alternatives needed by gcc-toolset-15-binutils-2.44-1.el9.x86_64
Fix that by always using the system alternatives with `--altdir`.
Related: RHEL-81741
