openssl vs. libgcrypt

[Karl Berry]

Hi Werner, Mauro, and all,

A generous volunteer (Logan Gabriel, cc'd) has been discussing offering
a long-time project of his for system integrity checking to GNU.

One of the things the project needs is ssl-ish computations,
such as provided by libgcrypt and openssl.

My immediate question is, is there some known/recommended set of
configure options for switching between these libraries?
wget currently has these:

  --without-ssl           disable SSL autodetection
  --with-libssl-prefix[=DIR]  search for libssl in DIR/include and DIR/lib
  --without-libssl-prefix     don't search for libssl in includedir and libdir

Perhaps these options could be extended.  If (say) --with-ssl=libgcrypt
is given, it would look for that library, using the libssl-prefix to
do so, if specified.  Similar if given --with-ssl=libopenssl.

I tried searching for "ssl" in other GNU configure scripts, but didn't
immediately see anything germane.

I gather the libgcrypt and openssl api's are not the same.  Logan was
going to implement a compatibility layer for the functionality he
needs.  Anyone have knowledge of previous work in this area?

Finally, there is the painful licensing problem.  About all I can think
of is to use the same special exception that is included with wget.

Any advice, reactions, ideas?

Thanks,
Karl