Merge pull request #1961 from skedgeme/master

add threads-extras, clock-extras, and next-ref to stackage

build-constraints.yaml

@@ -2518,6 +2518,11 @@ packages:
         - data-msgpack
         - network-msgpack-rpc
 
+    "Jonathan Fischoff <jonathangfischoff@gmail.com>":
+        - threads-extra
+        - clock-extras
+        - next-ref
+
     # If you stop maintaining a package you can move it here.
     # It will then be disabled if it starts causing problems.
     # See https://github.com/fpco/stackage/issues/1056