[lld] Set up .arcconfig to point to new Diffusion LLD repository

[benhamilton]

Summary

We want to automatically copy the appropriate mailing list
for review requests to the LLD repository.

For context, see the proposal and discussion here:

http://lists.llvm.org/pipermail/cfe-dev/2017-November/056032.html

Similar to D40179, I set up a new Diffusion repository with callsign
"LLD" for lld:

https://reviews.llvm.org/source/lld/

This explicitly updates lld's .arcconfig to point to the new C
repository in Diffusion, which will let us use Herald rule H270.

[ruiu]

.arcconfig

2

The official name of lld is "lld" and not "LLD".

[benhamilton]

.arcconfig

2

Yes, I made sure the name of the repository is "lld":

https://reviews.llvm.org/source/lld/

However, Phabricator repository callsigns are required to be "short uppercase strings":

https://secure.phabricator.com/book/phabricator/article/diffusion_managing/#basics-callsigns

Each repository can optionally be identified by a "callsign", which is a short uppercase string like "P" (for Phabricator) or "ARC" (for Arcanist).

So, I think we need to use LLD here for the callsign, and lld for the name of the repository, which is how I have set it up.

[ruiu]

Looks good, but I know little about .arcconfig, so I think you want to get a LGTM from someone who knows about it.

[sammccall]

The idea that I know about this is pretty funny :-)
But this is the same setup that's working well for clang-tools-extra and others.

.arcconfig

 {
-  "project_id" : "lld",
+  "repository.callsign" : "LLD",
   "conduit_uri" : "https://reviews.llvm.org/"
 }