Add generation of dependency file for .ap_ package

Make Aapt generate a dependency file in the same directory as the
output ap_ file if the --generate-dependencies flag is set.
This dependency file can then be read by the ant exec loop task
to see whether to repackage resources.

Change-Id: I763679414daf76369700aa599c26dcf78d4de099
diff --git a/tools/aapt/ZipFile.h b/tools/aapt/ZipFile.h
index 7877550..dbbd072 100644
--- a/tools/aapt/ZipFile.h
+++ b/tools/aapt/ZipFile.h
@@ -57,7 +57,7 @@
     /*
      * Open a new or existing archive.
      */
-    enum {
+    typedef enum {
         kOpenReadOnly   = 0x01,
         kOpenReadWrite  = 0x02,
         kOpenCreate     = 0x04,     // create if it doesn't exist