FOSS gamedev and creative worlds

Hello

Here is how I´ve worked around this Problem in Ubuntu 12.04 LTS.
I´ve Downloaded the Tarballs of libpng and zlib from theyr respective Websites
compiled and installed them.
At last I started minetest with the LD_LIBRARY_PATH

LD_LIBRARY_PATH=/usr/local/lib minetest

THat works perfectly for me.
Have Fun,
JPR