mingw32-libpng has broken dependencies in the epel-6 tree:
On ppc64:
mingw32-libpng-1.2.37-3.el6.noarch requires mingw32-runtime
mingw32-libpng-1.2.37-3.el6.noarch requires mingw32-filesystem >= 0:63
mingw32-libpng-1.2.37-3.el6.noarch requires mingw32(zlib1.dll)
mingw32-libpng-1.2.37-3.el6.noarch requires mingw32(msvcrt.dll)
mingw32-libpng-1.2.37-3.el6.noarch requires mingw32(kernel32.dll)
Please resolve this as soon as possible.
