mesa: update to version 26.2.1 - #156

Checking PR #156: mesa: update to version 26.2.1 (Makefile Audit)

Commit a6acab1 - mesa: update to version 26.2.1:

✅ PKG_VERSION bump matches context information inside subject line (26.2.1)
✅ Makefile does not assign per-package variables at the top level
✅ Makefile contains valid assignment operators and no spaces after ':='
✅ No feed package forces its own inclusion into buildbot default images via DEFAULT+BUILDBOT
✅ Makefile does not reuse PKG_NAME in call, define, or eval lines
✅ File additions contain clean UNIX (LF) line termination
✅ All modified files contain a trailing newline

Package Release Audit:

✅ Package libs/mesa version updated to '26.2.1' and PKG_RELEASE correctly reset to 1