Fence add_binary for pv

install/archiso

@@ -18,7 +18,12 @@ build() {
     add_binary truncate
     add_binary gpg
     add_binary grep
-    add_binary pv
+
+    if command -v pv > /dev/null 2>&1; then
+      add_binary pv
+    else
+      warning 'pv not found; falling back to cp for copy to RAM'
+    fi
 
     add_file /usr/lib/udev/rules.d/60-cdrom_id.rules
     add_file /usr/lib/udev/rules.d/10-dm.rules