Use the last of multi-buildpack's release script

Author: mars

bin/compile

@@ -61,6 +61,15 @@ if [ $? == 0 ]; then
   if [ $? != 0 ]; then
     exit 1
   fi
+
+  # check if the buildpack left behind an environment for subsequent ones
+  if [ -e $dir/export ]; then
+    source $dir/export
+  fi
+
+  if [ -x $dir/bin/release ]; then
+    $dir/bin/release $1 > $1/last_pack_release.out
+  fi
 else
   echo "create-react-app `.buildpacks` not defined. Exiting."
   exit 1

bin/release

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+if [ -e $1/last_pack_release.out ]; then
+  cat $1/last_pack_release.out
+  rm $1/last_pack_release.out
+else
+  echo "--- {}"
+fi