No longer need to find libpng when setting builds var as we have decided that libpng comes from homebrew on osx and from system on Linux, and is built by windows.
No longer need to find libpng when setting builds var as we have decided that libpng comes from homebrew on osx and from system on Linux, and is built by windows.

git-svn-id: 06aac1f7aa6783202dd435920b98a457d633d0b0@1572 a9e16012-fd73-49ee-95cb-036de7809213

Tech-XCorp/bilder