* lib/md2-stream.c: New file, extracted from lib/md2.c.
* lib/md2.c: Don't include stdlib.h, unlocked-io.h.
(BLOCKSIZE, md2_stream): Moved to md2-stream.c.
* lib/md2.h: Reorder declarations.
* modules/crypto/md2-buffer: New file, based on modules/crypto/md2.
* modules/crypto/md2: Rewritten.
