This port is for ILE (native OS/400) not PASE (PASE is almost like Unix, and already comes with openssl).
The idiosynchrasies are explained in the README.as400 file in AS400patch.tar.gz.
AS400patch.tar.gz (large patch for OpenSSL and other files):
https://drive.google.com/file/d/1pLDIiMTyJvKsl6Ntd7sV10kMvuGePrNX/view?usp=sharing
AS400_GNU.tar.gz (source for GNU/IBM tools required to build openssl in ILE environment):
https://drive.google.com/open?id=1DeKIE32nmUpvk7fvrcSYlflUn_k1CBso
The idiosynchrasies are explained in the README.as400 file in AS400patch.tar.gz.
AS400patch.tar.gz (large patch for OpenSSL and other files):
https://drive.google.com/file/d/1pLDIiMTyJvKsl6Ntd7sV10kMvuGePrNX/view?usp=sharing
AS400_GNU.tar.gz (source for GNU/IBM tools required to build openssl in ILE environment):
https://drive.google.com/open?id=1DeKIE32nmUpvk7fvrcSYlflUn_k1CBso