wipememory: use one-byte aligned type for unaligned memory accesses
* src/g10lib.h (fast_wipememory2_unaligned_head): Enable unaligned access only when HAVE_GCC_ATTRIBUTE_PACKED and HAVE_GCC_ATTRIBUTE_ALIGNED defined. (fast_wipememory_t): New. (fast_wipememory2): Use 'fast_wipememory_t'.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>