liquidhaskell: switch ghc-8.6.x version to the 'develop' branch to fix the build

pkgs/development/haskell-modules/configuration-ghc-8.6.x.nix

@@ -67,4 +67,25 @@ self: super: {
   # Break out of "yaml >=0.10.4.0 && <0.11": https://github.com/commercialhaskell/stack/issues/4485
   stack = doJailbreak super.stack;
 
+  # Needs a recent version from the "develop" branch of the upstream git
+  # repository to compile with ghc 8.6.4.
+  liquid-fixpoint = assert super.liquid-fixpoint.version == "0.7.0.7"; overrideSrc super.liquid-fixpoint {
+    src = pkgs.fetchFromGitHub {
+      owner = "ucsd-progsys";
+      repo = "liquid-fixpoint";
+      rev = "42c027ab9ae47907c588a2f1f9c05a5e0aa881e9";
+      sha256 = "17qmzq1vx7h04yd38drr6sh6hys3q2rz62qh3pna9kbxlcnikkqf";
+    };
+    version = "0.8.0.2-pre-release";
+  };
+  liquidhaskell = assert super.liquidhaskell.version == "0.8.2.4"; overrideSrc super.liquidhaskell {
+    src = pkgs.fetchFromGitHub {
+      owner = "ucsd-progsys";
+      repo = "liquidhaskell";
+      rev = "254e77da9cd36e95b72c526bfb9eec50d3447050";
+      sha256 = "089x41z51iw542ijz32j9ns6flcc4hsbjqx7rfznvmm7a4q78yza";
+    };
+    version = "0.8.6.0-pre-release";
+  };
+
 }

pkgs/development/haskell-modules/configuration-hackage2nix.yaml

@@ -2431,6 +2431,8 @@ package-maintainers:
     - lambdabot-core
     - lambdabot-irc-plugins
     - language-nix
+    - liquid-fixpoint
+    - liquidhaskell
     - logging-facade-syslog
     - nix-paths
     - pandoc
@@ -6570,8 +6572,6 @@ broken-packages:
   - lio-simple
   - lipsum-gen
   - liquid
-  - liquid-fixpoint
-  - liquidhaskell
   - liquidhaskell-cabal
   - liquidhaskell-cabal-demo
   - list-fusion-probe

pkgs/development/haskell-modules/hackage-packages.nix

@@ -143442,8 +143442,6 @@ self: {
        doCheck = false;
        description = "Predicate Abstraction-based Horn-Clause/Implication Constraint Solver";
        license = stdenv.lib.licenses.bsd3;
-       hydraPlatforms = stdenv.lib.platforms.none;
-       broken = true;
      }) {inherit (pkgs) git; inherit (pkgs) nettools; 
          inherit (pkgs) ocaml; inherit (pkgs) z3;};
 
@@ -143486,8 +143484,6 @@ self: {
        testSystemDepends = [ z3 ];
        description = "Liquid Types for Haskell";
        license = stdenv.lib.licenses.bsd3;
-       hydraPlatforms = stdenv.lib.platforms.none;
-       broken = true;
      }) {inherit (pkgs) z3;};
 
   "liquidhaskell-cabal" = callPackage