Comment 17 for bug 536161

The minizip sources of zlib-1.2.5 are very different to the ones we ship with widelands.

Best take would be not to touch them, I think... We should mark them with a "deprecated and slated for future removal" comment, so nobody fixes anything there except s/he knows what s/he does.
I will put the minizip sources inside a subdirectory (src/minizip) and make the CMake script issue a warning if those sources are used because system minizip is not found.