Use upstream nlohmann_json

release-common.nix

@@ -50,6 +50,7 @@ rec {
       bzip2 xz brotli editline
       openssl pkgconfig sqlite boehmgc
       boost
+      nlohmann_json
 
       # Tests
       git

release.nix

@@ -200,7 +200,7 @@ let
 
         doInstallCheck = true;
 
-        lcovFilter = [ "*/boost/*" "*-tab.*" "*/nlohmann/*" "*/linenoise/*" ];
+        lcovFilter = [ "*/boost/*" "*-tab.*" ];
 
         # We call `dot', and even though we just use it to
         # syntax-check generated dot files, it still requires some