distcc-avahi: 3.4-18 — fix DISTCC_ARGS/DISTCC_OPTS drift on upgrade (closes #5)

Stock distcc and earlier distcc-avahi releases ship /etc/conf.d/distccd
with DISTCC_ARGS=, while our distccd.service reads $DISTCC_OPTS. On
hosts that had stock distcc installed first, pacman keeps the existing
conf file (it's marked backup=) so the rename never happens — distccd
starts with empty options, falls back to --allow-private, and warns
about missing /usr/lib/distcc masquerade dir.

Add a post_install/post_upgrade .install hook that:
- detects DISTCC_ARGS= in /etc/conf.d/distccd and renames to DISTCC_OPTS=
  (keeping a timestamped backup beside it)
- runs update-distcc-symlinks if /usr/lib/distcc is unpopulated
- prompts the operator to restart distccd if it's already active

Bumps pkgrel to 18.

Hit on ampere 2026-04-29 during fourier-campaign distcc enrollment;
likely lurking on every host with stock-distcc legacy state.

arch/distcc-avahi/distcc-avahi.install

@@ -0,0 +1,30 @@
+_fix_conf() {
+    local conf=/etc/conf.d/distccd
+    if [ -f "$conf" ] && grep -q '^DISTCC_ARGS=' "$conf"; then
+        cp -a "$conf" "${conf}.pre-distcc-avahi-fix.$(date +%Y%m%d-%H%M%S)"
+        sed -i 's/^DISTCC_ARGS=/DISTCC_OPTS=/' "$conf"
+        echo "==> distcc-avahi: renamed DISTCC_ARGS -> DISTCC_OPTS in $conf"
+        echo "    (the systemd unit reads \$DISTCC_OPTS; backup left as ${conf}.pre-distcc-avahi-fix.*)"
+    fi
+}
+
+_warn_masq() {
+    if [ ! -d /usr/lib/distcc ]; then
+        echo "==> distcc-avahi: /usr/lib/distcc/ not populated; running update-distcc-symlinks"
+        /usr/bin/update-distcc-symlinks 2>/dev/null || true
+    fi
+}
+
+post_install() {
+    _fix_conf
+    _warn_masq
+}
+
+post_upgrade() {
+    _fix_conf
+    _warn_masq
+    if systemctl is-active --quiet distccd 2>/dev/null; then
+        echo "==> distcc-avahi: distccd.service is active; restart with"
+        echo "    'sudo systemctl restart distccd' to pick up any conf change"
+    fi
+}