openssh:
 * make openssh/digest.h self-contained (modified by freetz' no_ripemd.patch)
 * this is just a minor improvement of r11876, the patch from r11876 should also work
 * refs #2419


git-svn-id: file:///var/svn/freetz/trunk@11877 149334a1-2f27-0410-a3b9-fc62619ac1e6