Upstream no longer manually strips the cygwin dll and creates a debug file since https://cygwin.com/git/?p=newlib-cygwin.git;a=commit;h=99bb3e937a0fdbc1e3acbdc7cefb31e54a89a6ac This means the debug info now moved from msys2-runtime-devel to msys2-runtime staying in the DLL. We don't really want to install/ship debug infos by default, so we could either re-implement the debug info extraction manually again, or let makepkg build a separate "-debug" package, or just strip everything. Since the later is the least work and the least special compared to other packages, just enable stripping.
The patches for this package are auto generated and managed in git: https://github.com/msys2/Cygwin
Run ./update-patches.sh to re-create the patches.