[PATCH] sha2: new header <sha2.h>

[Roland McGrath]

You haven't said anything to justify the change.  People are giving you
feedback on the implementation details, but that should not be interpreted
as agreement with the effect of the change.  I don't think we have any
desire whatsoever to support new APIs in -lcrypt.  There are other
libraries that provide things like SHA implementations.  Just use those.