Original zlib minizip and newer minizip-ng are ABI incompatible.
tdesktop bundles old zlib minizip, but systems such as OpenBSD ship
minizip-ng as their "minizip" package.
http://zlib.net/ shows 1.2.11 as the latest version as of today.
Require the same major version to prevent detecting minizip-ng as
zlib minizip breaking the build.