msys2-runtime: Fix bugs causing hangs (#6717)
* msys2-runtime: Fix bugs causing hangs
This Pull Request backports three changes. The first one is a prerequisite for the second, and the third is also needed to fix those bugs that caused hangs that I first saw reported in https://github.com/msys2/MSYS2-packages/pull/6445:
1. `c892dfe93e`: the [complete prerequisite](https://github.com/cygwin/cygwin/commit/bbd3710fc83451426e3a58e5032437ca535fa444), including the companion `dtable.cc` standard-handle change.
2. `92c1e00a38`: [console-mode v18](https://inbox.sourceware.org/cygwin-patches/20260919004709.26360-1-takashi.yano@nifty.ne.jp/), including reconciliation on signal and read-retry paths.
3. `c770e1b9fa`: [owner-exit v5](https://inbox.sourceware.org/cygwin-patches/20260923223230.3504-1-takashi.yano@nifty.ne.jp/), including the processed-input fallback for an unavailable console master.
I verified that these patches are enough to address the hangs demonstrated by the reproducer provided in https://github.com/msys2/msys2-runtime/issues/351.
This fixes https://github.com/msys2/msys2-runtime/issues/351
This corresponds to https://github.com/msys2/msys2-runtime/pull/368
* msys2-runtime: fix pkgrelOoops! My script has a bug!
Co-authored-by: Christoph Reiter <reiter.christoph@gmail.com>
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Co-authored-by: Christoph Reiter <reiter.christoph@gmail.com>
msys2/MSYS2-packages@bca80c8