Drop COMPAT_INET4 support
Detail: Also remove ancient CMHG 5.16 and lingering TinyStubs support. Use agnostic TCPIPLibs: include path, case correct CMHG, so CI works. Admin: Submission for TCP/IP bounty.
Detail: Also remove ancient CMHG 5.16 and lingering TinyStubs support. Use agnostic TCPIPLibs: include path, case correct CMHG, so CI works. Admin: Submission for TCP/IP bounty.