Cleaned up a number of small tweaks in the scripts

- Added the littlefs license note to the scripts.

- Adopted parse_intermixed_args everywhere for more consistent arg
  handling.

- Removed argparse's implicit help text formatting as it does not
  work with perse_intermixed_args and breaks sometimes.

- Used string concatenation for argparse everywhere, uses backslashed
  line continuations only works with argparse because it strips
  redundant whitespace.

- Consistent argparse formatting.

- Consistent openio mode handling.

- Consistent color argument handling.

- Adopted functools.lru_cache in tracebd.py.

- Moved unicode printing behind --subscripts in traceby.py, making all
  scripts ascii by default.

- Renamed pretty_asserts.py -> prettyasserts.py.

- Renamed struct.py -> struct_.py, the original name conflicts with
  Python's built in struct module in horrible ways.

scripts/data.py

@@ -4,6 +4,13 @@
 # around nm with some extra conveniences for comparing builds. Heavily inspired
 # by Linux's Bloat-O-Meter.
 #
+# Example:
+# ./scripts/data.py lfs.o lfs_util.o -S
+#
+# Copyright (c) 2022, The littlefs authors.
+# Copyright (c) 2020, Arm Limited. All rights reserved.
+# SPDX-License-Identifier: BSD-3-Clause
+#
 
 import collections as co
 import csv
@@ -126,7 +133,7 @@ class DataResult(co.namedtuple('DataResult', 'file,function,data_size')):
 
 def openio(path, mode='r'):
     if path == '-':
-        if 'r' in mode:
+        if mode == 'r':
             return os.fdopen(os.dup(sys.stdin.fileno()), 'r')
         else:
             return os.fdopen(os.dup(sys.stdout.fileno()), 'w')
@@ -417,7 +424,7 @@ if __name__ == "__main__":
         nargs='*',
         default=OBJ_PATHS,
         help="Description of where to find *.o files. May be a directory "
-            "or a list of paths. Defaults to %(default)r.")
+            "or a list of paths. Defaults to %r." % OBJ_PATHS)
     parser.add_argument(
         '-v', '--verbose',
         action='store_true',
@@ -468,16 +475,16 @@ if __name__ == "__main__":
         '--type',
         default=TYPE,
         help="Type of symbols to report, this uses the same single-character "
-            "type-names emitted by nm. Defaults to %(default)r.")
+            "type-names emitted by nm. Defaults to %r." % TYPE)
     parser.add_argument(
         '--nm-tool',
         type=lambda x: x.split(),
         default=NM_TOOL,
-        help="Path to the nm tool to use. Defaults to %(default)r")
+        help="Path to the nm tool to use. Defaults to %r." % NM_TOOL)
     parser.add_argument(
         '--build-dir',
         help="Specify the relative build directory. Used to map object files "
             "to the correct source files.")
     sys.exit(main(**{k: v
-        for k, v in vars(parser.parse_args()).items()
+        for k, v in vars(parser.parse_intermixed_args()).items()
         if v is not None}))