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.
d24e4dabb9