DF-5561 kernel build log (inside guest, fix validation)

ATTEMPT 1 (17:1x, FAILED — kept for honesty):
  cd /usr/src && make -j6 buildkernel KERNCONF=X86_64_GENERIC
  => "You must buildworld before buildkernel." (bk_tools Error code 1;
     the with-src snapshot has no built world) — installkernel then
     installed a stale obj kernel; discarded.

ATTEMPT 2 (17:2x, SUCCESS — first patched kernel, "kernel #1 17:27:33"):
  cd /usr/src && patch -N -p1 < /root/df5561_fix.diff
    Patching file sys/platform/pc64/x86_64/db_interface.c using Plan A...  Hunk #1 succeeded at 168 (fuzz 2)
  cd /usr/src && make -j6 nativekernel KERNCONF=X86_64_GENERIC
  => >>> Kernel build for X86_64_GENERIC completed on Wed Oct  7 17:30:55 UTC 2026
  cd /usr/src && make installkernel KERNCONF=X86_64_GENERIC
  => >>> Kernel install for X86_64_GENERIC completed on Wed Oct  7 17:31:24 UTC 2026
  uname -v => DragonFly 6.5-DEVELOPMENT #1: Wed Oct  7 17:27:33 UTC 2026  root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC

ATTEMPT 3 (18:0x, SUCCESS — regeneration after snapshot reset for the
           preserved serial.patched.txt transcript, "kernel #1 18:06:01"):
  identical commands (patch verified: grep -c DF-5561 => 1)
  => >>> Kernel build for X86_64_GENERIC completed on Wed Oct  7 18:09:24 UTC 2026
  => >>> Kernel install for X86_64_GENERIC completed on Wed Oct  7 18:10:24 UTC 2026
  uname -v => DragonFly 6.5-DEVELOPMENT #1: Wed Oct  7 18:06:01 UTC 2026

Guest toolchain: native gcc80 (base system); no buildworld required for
nativekernel. Build wall time ~5-7 min on -smp 6.