make indent an os-indepdent routine

bin/compile

@@ -11,6 +11,14 @@ mktmpdir() {
   echo $dir
 }
 
+function indent() {
+  c='s/^/       /'
+  case $(uname) in
+    Darwin) sed -l "$c";;
+    *)      sed -u "$c";;
+  esac
+}
+
 # config
 NODE_VERSION="0.4.7"
 NPM_VERSION="1.0.27"
@@ -60,7 +68,7 @@ fi
 # install dependencies with npm
 echo "-----> Installing dependencies with npm $NPM_VERSION"
 cd $BUILD_DIR
-HOME="$BUILD_DIR" $VENDORED_NODE/bin/node $VENDORED_NPM/cli.js install 2>&1 | sed -u 's/^/       /'
+HOME="$BUILD_DIR" $VENDORED_NODE/bin/node $VENDORED_NPM/cli.js install 2>&1 | indent
 if [ "${PIPESTATUS[*]}" != "0 0" ]; then
   echo " !     Failed to install dependencies with npm"
   exit 1