Bear in mind that '*both* the conditions of the OpenSSL License *and* the original SSLeay license apply to the toolkit' [emphasis mine].
>The licence and distribution terms for any publically available version or
>derivative of this code cannot be changed. i.e. this code cannot simply be
>copied and put under another distribution licence
>[including the GNU Public Licence.]
So any derivative work must be released under the terms of the SSLeay license. This makes it incompatible with any copyleft license at the very least. For example, an MIT licensed piece of software can be combined with CDDL software, and the whole distributed under the CDDL, because adhering to the terms of the CDDL necessarily means adhering to the terms of the MIT license. With SSL, this is not the case; in fact it's similar to the GPL's requirement that no further restrictions be imposed, so probably has all the same incompatibilities.