error building libsdl2

~/Desktop/hw-master> /boot/home/haikuporter/haikuporter libsdl2
Checking if any package-infos need to be updated ...
Looking for stale package-infos ...
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media-libs::libsdl2-2.0.1
======================================================================
Encountered problems resolving package dependencies:
  1: nothing provides devel:libpng>=1.5 needed by faked_libsdl2-2.0.1-1
*** unable to resolve required ports for libsdl2-2.0.1
***     package-infos:
***             /boot/home/haikuports/media-libs/libsdl2/work-2.0.1/repository/libsdl2-2.0.1.PackageInfo
***             /boot/home/haikuports/media-libs/libsdl2/work-2.0.1/repository/libsdl2_devel-2.0.1.PackageInfo
***             /boot/home/haikuports/media-libs/libsdl2/work-2.0.1/repository/libsdl2_source-2.0.1.PackageInfo
***     repositories:
***             /boot/home/haikuports/packages
***