anchor.diff:    passthru = {
       shellPath = "/bin/git-shell";
       tests = {
  +      withInstallCheck = finalAttrs.finalPackage.overrideAttrs (_: {
  +        doInstallCheck = true;
  +      });
         buildbot-integration = nixosTests.buildbot;
       };
     };
  
positive.code:     platforms = lib.platforms.all;
      maintainers = with lib.maintainers; [ primeos wmertens globin ];
    };
  }
  
negative.code: , pkg-config, glib, libsecret
  , gzip # needed at runtime by gitweb.cgi
  , withSsh ? false
  , doInstallCheck ? !stdenv.isDarwin  # extremely slow on darwin
  }:
  
  assert osxkeychainSupport -> stdenv.isDarwin;
  