Switch to upstream 2.39 release
Upstream commit: ef321e23c20eebc6d6fb4044425c00e6df27b05f
- Document CVE-2023-6246, CVE-2023-6779, and CVE-2023-6780
- Update advisory format and introduce some automation
- manual/io: Fix swapped reading and writing phrase.
- Fix typo
- S390: Fix building with --disable-mutli-arch [BZ #31196]
- NEWS: insert advisories and fixed bugs for 2.39
- contrib.texi: update
- INSTALL, install.texi: minor updates, regenerate
- libc.pot: regenerate
- version.h, include/features.h: Bump version to 2.39
- Create ChangeLog.old/ChangeLog.28