Make xcrun wrapper search /usr/bin too

The usual xcrun would, and this wrapper exists to also work around broken xcode-select paths.

Library/ENV/4.3/xcrun

@@ -14,7 +14,7 @@ if [ $HOMEBREW_SDKROOT ]; then
     exec /usr/bin/xcrun "$arg0" "$@";;
   esac
 
-  path=$(/usr/bin/xcrun -find $arg0)
+  path="$(/usr/bin/xcrun -find $arg0)"
   [ -x "$path" ] && exec "$path" "$@"
 
   # Nuts, Xcode is not setup properly or something.
@@ -23,6 +23,8 @@ if [ $HOMEBREW_SDKROOT ]; then
   [ -x "$path" ] && exec "$path" "$@"
   path="/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/$arg0"
   [ -x "$path" ] && exec "$path" "$@"
+  path="/usr/bin/$arg0"
+  [ -x "$path" ] && exec "$path" "$@"
 
   echo "Your Xcode setup is not ready. You need to either:"
   echo "    sudo xcode-select -switch /path/to/Xcode.app"