Finally made it compile through and I now can execute the netpgp command
on z/OS, now we can test all the basic functions and develop from here.
It now automatically detects whether it should build use
GSK SSL or OpenSSL for building the backend.
Enabling autoheader to actually work and adding initial check function
structure for detecting whether we're on z/OS with GSKSSL or on a system
which has OpenSSL.