Is there a specific reason to choose the name T? FWICS different drivers use different names but I think Triple is both more popular and more readable.
Use 'Triple' instead of 'T'.
No specific reason, I agree using the Triple name is a better choice. I updated the diff.
LGTM (I'm presuming you've tested it and not testing it myself ;-)).
Yes, I rebuilt everything with the updated diff and ran check-clang-driver.