Add support for config file

dropbear_install

@@ -2,6 +2,7 @@
 
 set -e
 
+CONFIG_FILE="/etc/dropbear/config"
 KEY_TYPES="ed25519 ecdsa rsa"
 
 get_fingerprint() {
@@ -83,6 +84,12 @@ build() {
     add_dir "/var/log"
     touch "${BUILDROOT}"/var/log/lastlog
 
+    if [ -s $CONFIG_FILE ]; then
+        echo "Using config file $CONFIG_FILE:"
+        cat $CONFIG_FILE
+        add_file $CONFIG_FILE
+    fi
+
     add_runscript
 }