Revert duplicated implemenation of --custom-targets

Author: Garrett

tools/build.py

@@ -53,9 +53,6 @@
     parser.add_argument("--source", dest="source_dir", type=argparse_filestring_type,
                         default=None, help="The source (input) directory", action="append")
 
-    parser.add_argument("--custom-targets", dest="custom_targets_directory", type=argparse_filestring_type,
-                        default=None, help="Specify directory containing custom_targets.json", action="append")
-
     parser.add_argument("--build", dest="build_dir", type=argparse_dir_not_parent(ROOT),
                       default=None, help="The build (output) directory")