Two S-sized improvements from BUILD-SYSTEM-IMPROVEMENTS.md:
1. local/scripts/audit-patch-idempotency.py (improvement #3):
Validates that every external patch in local/patches/ is
idempotent (--reverse --check succeeds) and reproducible
(re-clone + re-apply produces an identical tree). Catches the
patch idempotency class of bug at lint time, where it used to
surface as a 2+ hour cookbook failure during a cook. Found a
real bug on first run: local/patches/libdrm/02-redox-dispatch.patch
has a hunk at xf86drm.c:321 that no longer matches the upstream
libdrm-2.4.125.
2. src/cook/script.rs auto-link Qt sysroot dirs (improvement #8):
The cookbook's BUILD_PRESCRIPT now auto-detects if the per-recipe
sysroot has Qt6 (qtbase or qtdeclarative) and creates the canonical
/usr/{plugins,mkspecs,metatypes,modules} symlinks that KF6 recipes
need for cmake to find Qt6Config.cmake's INTERFACE_* paths. New
KF6 recipes that depend on qtbase no longer need to manually
call redbear_qt_link_sysroot_dirs in their build script. Recipes
that need more customization can still call the helper directly
via 'source $COOKBOOK_ROOT/local/scripts/lib/qt-sysroot.sh'.
kellito