assymetric encryption functions based on OpenSSL

Hi I'm about to add an extension I called openssl. When configured with --with-openssl the extension will be included and offers functions for assymetric encryption (both encrypting and signing data). More functions based on openssl will hopefully be added later by me or others. I have a question though. It looks like most extensions have a dsp- file that I guess is used when building the extension on Windows. I haven't got a dsp-file, what happens if people try to build the extension on Windows? Should a dsp-file be created? How? Stig