fix banjo depfile

Change-Id: Ic76dc8fd6a6cd9b81e1a221e124b0f45f65fc072
diff --git a/public/gn/banjo.gni b/public/gn/banjo.gni
index ac5f9f7..a09bbf4 100644
--- a/public/gn/banjo.gni
+++ b/public/gn/banjo.gni
@@ -144,7 +144,8 @@
         gen_depfile,
       ]
       script = "$zx/public/gn/gen-fidlc-rsp.sh"
-      args = rebase_path(outputs + sources, root_build_dir) + gen_args
+      args = rebase_path(outputs + [ gen_outputs[0] ] + sources,
+                         root_build_dir) + gen_args
     }
 
     # Finally, the real action runs banjoc with that response file.
diff --git a/public/gn/gen-fidlc-rsp.sh b/public/gn/gen-fidlc-rsp.sh
index 43d85c6..4766a3e 100755
--- a/public/gn/gen-fidlc-rsp.sh
+++ b/public/gn/gen-fidlc-rsp.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 #
-# Copyright 2018 The Fuchsia Authors. All rights reserved.
+# Copyright 2019 The Fuchsia Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
@@ -8,8 +8,9 @@
 
 OUTFILE="$1"
 DEPFILE="$2"
-RSPFILE="$3"
-shift 3
+DEPOUTFILE="$3"
+RSPFILE="$4"
+shift 4
 
 ARGS=()
 FILES=()
@@ -42,5 +43,5 @@
 
 handle_args "$@"
 read_rspfile < "$RSPFILE"
-echo "$OUTFILE: ${FILES[*]}" > "$DEPFILE"
+echo "$DEPOUTFILE: ${FILES[*]}" > "$DEPFILE"
 write_output > "$OUTFILE"