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[x] feature request
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Current behavior
ngc --help and ng-xi18n --help do not display help text, instead it does the usual action.

Expected behavior
ngc --help and ng-xi18n --help should display the command line and modifiers supported by the tools.

Minimal reproduction of the problem with instructions
Run ngc --help in a terminal

What is the motivation / use case for changing the behavior?
Most command line tools implement --help and -h flags to display some help text (with the various supported modifiers) and the version. The compiler-cli tools should do the same as it provides an easy way to figure out how to tweak command line and scripts to get the expected behaviours.

See for instance npm --help, yarn --help, tsc --help or webpack --help for similar help texts.

--version would also be a nice to have but not as critical I guess.

• Angular version: 2.4.9
• Browser: n/a
• Language: n/a
• Node (for AoT issues): node --version = 4.7.2