Add target in j2cl using GWT's source JRE emulation

Note: This does not yet switch over J2Cl to actually use this target.

Change-Id: If2d3e299a293f7d4f30e09add726d816c9b50683
Review-Link: https://gwt-review.googlesource.com/#/c/13403/
diff --git a/dev/BUILD b/dev/BUILD
index bc36f70..fb67927 100644
--- a/dev/BUILD
+++ b/dev/BUILD
@@ -334,3 +334,11 @@
     srcjars = [":dev-test-code"],
     tests = GWT_DEV_TESTS,
 )
+
+filegroup(
+    name = "emul",
+    srcs = glob([
+        "core/super/javaemul/**/*.java",
+    ]),
+    visibility = ["//third_party/java_src/j2cl:__subpackages__"],
+)
diff --git a/user/BUILD b/user/BUILD
index 3fd5814..3ce86ce 100644
--- a/user/BUILD
+++ b/user/BUILD
@@ -643,3 +643,13 @@
         exclude = ANT_EXCLUDES,
     ),
 )
+
+filegroup(
+    name = "emul",
+    srcs = glob(
+        [
+            "super/com/google/gwt/emul/java/**/*.java",
+        ],
+    ),
+    visibility = ["//third_party/java_src/j2cl:__subpackages__"],
+)