A main program that takes as input a source Dart file and a number of ARB files representing translations of messages from the corresponding Dart file. See extract_to_arb.dart and make_hardcoded_translation.dart.
If the ARB file has an @@locale or _locale value, that will be used as the locale. If not, we will try to figure out the locale from the end of the file name, e.g. foo_en_GB.arb will be assumed to be in en_GB locale.
This produces a series of files named