emulators/libc6-shim: Update 20251025 => 20260426
Commit log:
https://github.com/shkhln/libc6-shim/compare/20251025...20260426
While here:
- Remove unnecessary GH_PROJECT - it's default value.
- Split long lines in post-patch.
- Merge MKDIRs in do-install.
PR: 294834
Sponsored by: UNIS Labs
(cherry picked from commit 8bc63e36911e7361c397574599f42b4623ccda28)