Bug 574376: Make checksetup.pl recommend JSON::XS to speed up the JSON-RPC

Bugzilla/Install/Requirements.pm

@@ -239,6 +239,13 @@ sub OPTIONAL_MODULES {
         feature => ['jsonrpc'],
     },
     {
+        package => 'JSON-XS',
+        module  => 'JSON::XS',
+        # 2.0 is the first version that will work with JSON::RPC.
+        version => '2.0',
+        feature => ['jsonrpc_faster'],
+    },
+    {
         package => 'Test-Taint',
         module  => 'Test::Taint',
         version => 0,

template/en/default/setup/strings.txt.pl

@@ -57,6 +57,7 @@ END
     feature_inbound_email     => 'Inbound Email',
     feature_jobqueue          => 'Mail Queueing',
     feature_jsonrpc           => 'JSON-RPC Interface',
+    feature_jsonrpc_faster    => 'Make JSON-RPC Faster',
     feature_new_charts        => 'New Charts',
     feature_old_charts        => 'Old Charts',
     feature_mod_perl          => 'mod_perl',