am 3c3a7e1f: (-s ours) am 791d8f2e: Upgrading libpng to 1.2.46 to fix a few vulnerabilities. DO NOT MERGE

* commit '3c3a7e1f0fbff859b3aaff19069aee5d623a1f75':
  Upgrading libpng to 1.2.46 to fix a few vulnerabilities. DO NOT MERGE