File baselibs.conf of Package libpng12-0
libpng-devel requires -libpng-<targettype> requires "libpng12-0-<targettype> = <version>" libpng12-0 obsoletes "libpng-<targettype> <= <version>" provides "libpng-<targettype> = <version>"
libpng-devel requires -libpng-<targettype> requires "libpng12-0-<targettype> = <version>" libpng12-0 obsoletes "libpng-<targettype> <= <version>" provides "libpng-<targettype> = <version>"