ok pedro@, millert@

The Pad function does padding like in Final but does not finish processing.
The FileChunk function creates a digest from a portion of a file.
Also made the length parameters consistent (and size_t).

functions can take a NULL buf pointer.  They will malloc memory as
needed in this case.

previously lived in foohl.c.  The foohl.c files are now generated
via sed, though perhaps cpp could be used in the future.
Use u_int8_t instead of unsigned char for the buffers struct fooContext.
Add constants for buffer lengths and use them in function prototypes
and the man pages.
This is basically cosmetic surgery; there should be no functional changes.
OK deraadt@

u_char -> unsigned char
u_short -> unsigned short
u_long -> unsigned long
u_int -> unsigned int
okay millert@

__minbytes__ checks where appropriate.  tested by itojun@
fixes PR 3505 from Janjaap van Velthooven

ok deraadt@

You must have an up-to-date gcc for this!
deraadt@ ok

o Add __BEGIN_DECLS/__END_DECLS to include files
o Safe macros
o Remove useless variable assignment in the End function of *hl.c
o Some minor KNF, needs more
From Dan Weeks

ftp://ftp.rsasecurity.com/pub/cryptobytes/crypto3n2.pdf, ok deraadt@

entire trees for testing anyway, I might as well do this intrusive touching
of include files now.  Added openBSD tags.

Antoon Bosselaers and massaged by me to fit the mdX(3) API.