Make 'idmap --scan' accept more than one input directory

The 'idmap --scan' command was limited to only scan a single directory
for overlay packages. Update idmap to support any number of directories.

Change-Id: I851f5720a3c1d844235911a0833670652a20a3c8
diff --git a/cmds/idmap/idmap.h b/cmds/idmap/idmap.h
index f507dd8..8d4210b 100644
--- a/cmds/idmap/idmap.h
+++ b/cmds/idmap/idmap.h
@@ -1,9 +1,11 @@
+
 #ifndef _IDMAP_H_
 #define _IDMAP_H_
 
 #define LOG_TAG "idmap"
 
 #include <utils/Log.h>
+#include <utils/Vector.h>
 
 #include <errno.h>
 #include <stdio.h>
@@ -26,8 +28,8 @@
 // Regarding target_package_name: the idmap_scan implementation should
 // be able to extract this from the manifest in target_apk_path,
 // simplifying the external API.
-int idmap_scan(const char *overlay_dir, const char *target_package_name,
-        const char *target_apk_path, const char *idmap_dir);
+int idmap_scan(const char *target_package_name, const char *target_apk_path,
+        const char *idmap_dir, const android::Vector<const char *> *overlay_dirs);
 
 int idmap_inspect(const char *idmap_path);