Also explicitly specify `-mstrict-align` (The current default `-mcpu`
on gcc doesn't support unaligned accesses, so aligned memory accesses
are already implicitly required).
The `-Wcast-align` warning seems to oversensitive as it flags code like
this: https://godbolt.org/z/c8481o8aa
This used to be added for aarch64 in a473cfd71b, but was later removed
in 11896868d6.
