net/hanstunnel: update to 0.4.4 [1] and improve

• Revert r326014 as nothing to substitute in pkg-message [1]
• Clarify server works only on Linux [1]
• Unbreak build on DragonFly [2]
• Drop poorly maintained CLANG option [3]
• Simplify patching via MAKE_ARGS
• Respect LOCALBASE != PREFIX
• Pet portlint (makepatch)
• Clarify LICENSE

PR: 195313
Reported by: DPorts [2]
Requested by: many [3]
Submitted by: vsityz@gmail.com (maintainer [1], based on)
Reviewed by: marino [2]
Approved by: maintainer timeout (~3 weeks)