Fix the build system changes that handle the autoconf cache patches.
The beforeconfigure target doesn't work as expected and causes
extra configure script executions and sometimes full rebuilds.
replace it by more ad-hoc code to generate a local autoconf cache for
the packages that need it (currently libpng and libXfont2)
ok miod@
Merge fixes from upstream for multiple Xserver issues:
* CVE-2026-33999: XKB Integer Underflow in XkbSetCompatMap()
* CVE-2026-34000: XKB Out-of-bounds Read in CheckSetGeom()
* CVE-2026-34001: XSYNC Use-after-free in miSyncTriggerFence()
* CVE-2026-34002: XKB Out-of-bounds read in CheckModifierMap()
* CVE-2026-34003: XKB Buffer overflow in CheckKeyTypes()
from matthieu@
this is errata/7.7/034_xserver.patch.sig
Merge fixes from upstream for multiple Xserver issues:
* CVE-2026-33999: XKB Integer Underflow in XkbSetCompatMap()
* CVE-2026-34000: XKB Out-of-bounds Read in CheckSetGeom()
* CVE-2026-34001: XSYNC Use-after-free in miSyncTriggerFence()
* CVE-2026-34002: XKB Out-of-bounds read in CheckModifierMap()
* CVE-2026-34003: XKB Buffer overflow in CheckKeyTypes()
from matthieu@
this is errata/7.8/028_xserver.patch.sig