• Allow the configure script to use any zlib version rather than requiring 1.1.3 or 1.1.4 (the program requires zlib >= 1.1.3, which was imported in January 1999) [1]
• Refactor pkg-plist as PLIST_FILES/PORTDOCS
• Polish the Makefile

[1]:
PR: ports/82524
Submitted by: Andrew McNaughton <andrew@scoop.co.nz>