socket-util: tighten aignment check for CMSG_TYPED_DATA()

socket-util: tighten aignment check for CMSG_TYPED_DATA()

Apparently CMSG_DATA() alignment is very much undefined. Which is quite
an ABI fuck-up, but we need to deal with this. CMSG_TYPED_DATA() already
checks alignment of the specified pointer. Let's also check matching
alignment of the underlying structures, which we already can do at
compile-time.

See: #27241

(This does not fix #27241, but should catch such errors already at
compile-time instead of runtime)