wipememory: use memset for non-constant length or large buffer wipes
* src/g10lib.h (CONSTANT_P): New. (_gcry_wipememory2): New prototype. (wipememory2): Use _gcry_wipememory2 if _len not constant expression or lenght is larger than 64 bytes. (FASTWIPE_T, FASTWIPE_MULT, fast_wipememory2_unaligned_head): Remove. (fast_wipememory2): Always handle buffer as unaligned. * src/misc.c (__gcry_burn_stack): Move memset_ptr variable to... (memset_ptr): ... here. New. (_gcry_wipememory2): New.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>