Our g++-aarch64 depends on libstdc++ with its same pkgver
We don't create a subpackage for libstdc++, so what should be
libstdc++-aarch64 lives in gcc-aarch
gcc-aarch cannot resolve to itself, so resolves to the libstdc++
provided by alpine
The solver goes nuts
This warranties that cross-compilers keep working, even when out-of-sync
with alpine. I really don't know why this wasn't added in so many years,
so I hope there's no hidden trick
