Implement --compression and --dont_change_compression.

--
MOS_MIGRATED_REVID=130541462

src/tools/singlejar/BUILD

diff --git a/src/tools/singlejar/BUILD b/src/tools/singlejar/BUILD
index 069b462..6dc6189 100644
--- a/src/tools/singlejar/BUILD
+++ b/src/tools/singlejar/BUILD
@@ -126,6 +126,7 @@
     data = [
         ":data1",
         ":data2",
+        ":stored_jar",
         ":test1",
         ":test2",
         "//external:jar",
@@ -322,3 +323,11 @@
         "data/extra_file3",
     ],
 )
+
+genrule(
+    name = "stored_jar",
+    srcs = ["output_jar.cc"],
+    outs = ["stored.jar"],
+    cmd = "$(location //external:jar) -0cf \"$@\" $(location :output_jar.cc)",
+    tools = ["//external:jar"],
+)