Release v3.13.2.549 (GDAL 3.13.2)

Highlights

• Bump GDAL to 3.13.2
• Linux build base moved debian:11 -> debian:12 (bookworm). gcc 12 and autoconf 2.71 are native there, so the apt-pin and the autoconf-from-source build are both retired; added a gcc >= 12 / autoconf >= 2.71 assertion and --break-system-packages for PEP 668
• Minimum glibc for the Linux packages is 2.35 (Ubuntu 22.04+, Debian 12+). Not trixie: its glibc 2.41 would exceed Ubuntu 24.04's 2.39 and break current-LTS users
• vcpkg baseline moved to release 2026.07.29 (9e593bb18e). Picks up libaec 1.1.7 from GitHub instead of gitlab.dkrz.de, which returns HTTP 429 for that archive from any IP
• Two ports held back deliberately, both with exit conditions: expat 2.7.4 (2.8.x uses arc4random_buf, a glibc 2.36 symbol, which would raise the floor for every shipped package) and arrow 23.0.1 (still references the removed C++20 draft std::log2p1 behind a feature check that misfires on Apple Clang)
• New CI gate: ci/check-glibc-floor.sh asserts the glibc floor against every shipped ELF and names the offending symbols on failure. It runs per-arch before any upload, so a package that would break Ubuntu 22.04 cannot be published. First run measured 73 shipped ELF binaries per arch with the ceiling at exactly GLIBC_2.35, so the floor is binding rather than slack
• CI repairs: pinned windows-2022 (the windows-latest alias had rolled to VS 2026 while the toolchain still assumes v143), removed the builds-<os>- restore-keys fallback that could restore build outputs across a dependency change, and added ci/Dockerfile.unix to the buildx cache key

What's Changed

• GDAL v3.13.2 + debian:12 build base by @MaxRev-Dev in #234

Full Changelog: v3.13.1.534...v3.13.2.549