Add `depfile` output flags to `dart compile`

[matanlurey]

The Dart SDK internal binaries, such as gen_snapshot support a depsfile output:

sdk/runtime/bin/main_options.cc

Line 794 in a3c6d05

" (--depfile-output-filename or --snapshot).\n");

The Flutter tool, and Flutter engine, use this option to correctly rebuild from various build systems.

It would be nice to have this available in dart compile so that Dart SDK internal binaries are (less?) not needed.

[dart-github-bot]

Summary: The user requests the addition of depfile output flags to the dart compile command, similar to the functionality available in internal Dart SDK binaries like gen_snapshot. This would allow for more flexible build systems and potentially reduce reliance on internal binaries.

[matanlurey]

Ben to add some context to this request as well: flutter/flutter#155769. Thanks!