Topic: building for STM with SSL and third party wifi stack

So I want to use SFTP with a product that has STM processor, we have incorporated  SSL with a third party wifi stack. I have some questions about how to build SSH and use SFTP.
We dont have a file system either.
I see a include statement #include <config.h> but I cant find a config.h in any of the subdirs of SSH (using 1.3.0).
Clearly I need to configure the build to not use any file access functions and I also need to configure the build to just use the third party send/receive funcitons.
what include files do I need to review/modify?