Add OpenBSD build VM and dtail package infrastructure

Add a QEMU/KVM OpenBSD VM for native compilation of CGo packages
(e.g. dtail with DataDog/zstd). The VM is fully automated via expect
driving the serial console installer.

- packages/buildvm/: setup, provision, start, stop scripts and expect installer
- packages/scripts/pkg-dtail-openbsd.sh: multi-binary package with signify signing
- packages/Makefile: build VM management and dtail-openbsd target using git archive
- frontends/Rexfile: dtail_install task uses custom pkg repo, dtail task enabled

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/packages/buildvm/stop.sh b/packages/buildvm/stop.sh
new file mode 100755
index 0000000..923ddaa
--- /dev/null
+++ b/packages/buildvm/stop.sh
@@ -0,0 +1,34 @@
+#!/bin/bash
+# Shut down the OpenBSD build VM gracefully.
+
+set -e
+
+VMDIR="$(cd "$(dirname "$0")" && pwd)"
+PIDFILE="$VMDIR/qemu.pid"
+SSH_PORT=2222
+
+if [ ! -f "$PIDFILE" ] || ! kill -0 "$(cat "$PIDFILE")" 2>/dev/null; then
+    echo "Build VM is not running."
+    rm -f "$PIDFILE"
+    exit 0
+fi
+
+echo "Shutting down build VM..."
+# Graceful shutdown via SSH, fall back to SIGTERM
+ssh -q -o ConnectTimeout=5 -p "$SSH_PORT" pbuild@localhost "doas halt -p" 2>/dev/null || true
+
+# Wait for QEMU process to exit
+PID=$(cat "$PIDFILE")
+for i in $(seq 1 15); do
+    if ! kill -0 "$PID" 2>/dev/null; then
+        echo "VM stopped."
+        rm -f "$PIDFILE"
+        exit 0
+    fi
+    sleep 1
+done
+
+# Force kill if still running
+echo "Force-killing QEMU (PID $PID)..."
+kill "$PID" 2>/dev/null || true
+rm -f "$PIDFILE"