GCC9 introduced an address-of-packed-member warning that triggers in
esc_coe.c. The issue is that a packed struct has an overall alignment
of 1, and taking the address of a member in a packed struct is not
guaranteed to have any particular alignment. However, in esc_coe these
structs are always overlayed on aligned memory so in practice there is
no problem.
Fix the problem by explicitly setting the minimum alignment for the
structs used in this manner. Also fix an instance where an unaligned
pointer was used but never dereferenced (by changing the type of the
pointer from uint32_t* to void*).
097477035d