Clippy is a compiler wrapper for rust that provides an extra layer of
linting. It's quite popular, but unfortunately doesn't provide the
output of the compiler that it's wrapping in it's output, so we don't
detect that clippy is rustc. This small patch adds a new compiler class
(that is the Rustc class with a different id) and the necessary logic to
detect that clippy is in fact rustc)
Fixes: #8767
This adds a new keyword argument to the init method, `allow_fail`. When
set to True (default is False) then a failure to configure is not an
error, and output is still returned. This can be useful for cases where
we expect initialization to fail, and want to check the output.
There are two problems with having this in the try/except block. The
first is that both of the if statements will raise, and the except
statement cathces `Exception`, so it catches these two cases, prints a
message that we either don't want or already printed, then re-raises.