uriparser: Fix cross building

When cross building, we need to disable building tests or cmake will
complain about the missing gtest.

Also switching from targetPlatform to buildPlatform caused doCheck to be
properly set to false

pkgs/development/libraries/uriparser/default.nix

@@ -14,10 +14,10 @@ stdenv.mkDerivation rec {
 
   cmakeFlags = [
     "-DURIPARSER_BUILD_DOCS=OFF"
-  ];
+  ] ++ lib.optional (!doCheck) "-DURIPARSER_BUILD_TESTS=OFF";
 
   checkInputs = [ gtest ];
-  doCheck = stdenv.targetPlatform.system == stdenv.hostPlatform.system;
+  doCheck = stdenv.buildPlatform == stdenv.hostPlatform;
 
   meta = with lib; {
     homepage = "https://uriparser.github.io/";