Add support for multiple asset dirs (-A)

Bug: 12608034
Change-Id: I02c5a1a73b83498d799570428cca3dd914f8ac11
diff --git a/tools/aapt/Main.cpp b/tools/aapt/Main.cpp
index 977226b..d1d3deb 100644
--- a/tools/aapt/Main.cpp
+++ b/tools/aapt/Main.cpp
@@ -345,7 +345,7 @@
                     goto bail;
                 }
                 convertPath(argv[0]);
-                bundle.setAssetSourceDir(argv[0]);
+                bundle.addAssetSourceDir(argv[0]);
                 break;
             case 'G':
                 argc--;