Merge pull request #2578 from sinelaw/patch-4

Add hexpat, several hxt-* and uncomment xml-to-json that depends on those

build-constraints.yaml

@@ -1507,13 +1507,18 @@ packages:
         # - hmatrix-repa # via repa: bounds: vector
 
     "Noam Lewis <jones.noamle@gmail.com> @sinelaw":
-        # - xml-to-json # via: hexpat
+        - xml-to-json
         - xml-to-json-fast
+        - resolve-trivial-conflicts
+        - wl-pprint
+        # not a maintainer
+        - hxt-curl
+        - hxt-expat
+        - hxt-tagsoup
+        - hexpat
         - digits
         - unification-fd
         - logict
-        - resolve-trivial-conflicts
-        - wl-pprint
         - leveldb-haskell
         - system-argv0
         - markdown-unlit