Use new helpers option

nix/default.nix

@@ -7,7 +7,5 @@ plugins.helpers.simple_plugin
      name = "frama-clang";
      deps = [ pkgs.llvmPackages_7.clang-unwrapped pkgs.llvm_7 pkgs.gnused ];
      opamPackages = [ "camlp4" ];
-     postPatch = ''
-     sed -i Makefile.config.in -e "s&@CLANG_INCDIR@&${pkgs.llvmPackages_7.clang-unwrapped}/include&"
-     '';
+     configure_options = "-with-clang-includedir=${pkgs.llvmPackages_7.clang-unwrapped}";
    }

nix/frama-ci.nix

@@ -5,7 +5,7 @@ let
     src = builtins.fetchGit {
             "url" = "https://bobot:${password}@git.frama-c.com/frama-c/Frama-CI.git";
             "name" = "Frama-CI";
-            "rev" = "8bb9694075309fb38c7d7cb28e831132de34ba04";
+            "rev" = "a99329415497d43b9bd263bbbbbded12e08f518b";
             "ref" = "feature/frama-clang-ci";
     };
  in