[util] Add in _Z_OF redefinition for gentoo and derivatives. Ref: https://bugs.launchpad.net/widelands/+bug/536161/comments/5
[util] Add in _Z_OF redefinition for gentoo and derivatives. Ref: https://bugs.launchpad.net/widelands/+bug/536161/comments/5

git-svn-id: 39e099a8ed5324aded674b764a67f7a08796d9a7@7555 662fdd30-d327-0410-a531-f549c87e1e9e

boyjimeking/paintown,Sevalecan/paintown,Sevalecan/paintown,Sevalecan/paintown,boyjimeking/paintown,Sevalecan/paintown,Sevalecan/paintown,Sevalecan/paintown,Sevalecan/paintown,boyjimeking/paintown,boyjimeking/paintown,boyjimeking/paintown,Sevalecan/paintown,boyjimeking/paintown,boyjimeking/paintown,boyjimeking/paintown