Improve robustness of valid() in pkzip format.
Make valid() in sunmd5 format robust.
Fix a crash in dynamic with an overlong salt.
Merge branch 'bleeding-jumbo' into memdbg

* bleeding-jumbo:
  Fix a crash in dynamic with an overlong salt.
  Make valid() in sunmd5 format robust.
  Improve robustness of valid() in pkzip format.