global var replaced by thread local

stdlib/ktSrc/modules/ModuleBuilder.kt

@@ -6,7 +6,7 @@ import jet.modules.*
 fun module(name: String, callback:  ModuleBuilder.() -> Unit) {
     val builder = ModuleBuilder(name)
     builder.callback()
-    AllModules.modules?.add(builder)
+    AllModules.modules.sure().get()?.add(builder)
 }
 
 class SourcesBuilder(val parent: ModuleBuilder) {

stdlib/src/jet/modules/AllModules.java

@@ -22,5 +22,14 @@ package jet.modules;
 import java.util.ArrayList;
 
 public class AllModules {
-    public static final ArrayList<Module> modules = new ArrayList<Module>();
+
+    public static final ThreadLocal<ArrayList<Module>> modules = new ThreadLocal<ArrayList<Module>>() {
+        @Override
+        protected ArrayList<Module> initialValue() {
+            return new ArrayList<Module>();
+        }
+    };
+
+    private AllModules() {
+    }
 }