Update libpng to fix compatibility with older macOS versions

See https://github.com/wxWidgets/libpng/pull/5
This commit is contained in:
Vadim Zeitlin
2020-12-30 23:33:03 +01:00
parent c069a62bd6
commit 28348b578a

Submodule src/png updated: 3ffeff7877...9853c67ab4