You ship your own build of the OpenSSL library that the VDDK is linked again. I would like to avoid library compatability issues by using the same OpenSSL library for my application code as is used for VDDK libraries - but that requires access to the headers files.
I expected the SSL source code to be included in the open source tarball. I think it should be - even if its not strictly needed for license reasons its good security practise to include the source code so that others can confirm there are no issues with it.