Mass-enabling D => License question

[Max Barraclough via Digitalmars-d]

The DMD frontend is licensed under the GPL, which is 'viral': if
your code links against it, you'll have to release your code as
GPL.

Strictly, John is right in that the GPL doesn't prevent you from
charging for your code, but seeing as that code will be GPL'ed,
anyone who buys it will then be free to share it publicly free of
charge. (You're also required to provide source.)

John's idea of having the user provide DMD, rather than bundling
it, may or may not be against the letter of the GPL (I'm unsure,
but I don't think it's exactly safe ground - your code is still
written to the DMD ABI, after all), but it's certainly against
the spirit.

Here is the official GPL FAQ:
https://www.gnu.org/licenses/gpl-faq.html

If I were you, I'd be asking: are there working D frontends
available other than DMD (from other IDE/compiler/tooling
projects)? If so, what's their licence? (I'm afraid I don't know
the answer to either.)

Usual disclaimer: I'm not a lawyer, certainly not a copyright
lawyer, certainly not your lawyer, etc.