LDC 1.0.0 not working on Travis CI on OSX?

[Jeremy DeHaan via digitalmars-d-ldc]

I recently upgraded my .travis.yml to include some new LDC 
versions, and they all work except for 1.0.0 on OSX.

When the ldmd command is run, I see the following error:

dyld: Library not loaded: /opt/local/lib/libconfig.9.dylib

   Referenced from: /Users/travis/dlang/ldc-1.0.0/bin/ldmd2

   Reason: image not found

0.16.1, 0.17.2, 1.1.0, and 1.2.0-beta all work on OSX; 1.0.0 is 
the only one that gives me this error.

Any idea what's going on here?