Symlink application lib directory when on SD card

This will help legacy games that use dlopen() to directly access the
/data/data/<app>/lib directory before the
ApplicationInfo.nativeLibraryDir was part of the API.

Change-Id: Ie9f3e7239b6334708b5d086ffafe66a507f6d9da
diff --git a/cmds/installd/installd.h b/cmds/installd/installd.h
index 479e4b2..59475e9 100644
--- a/cmds/installd/installd.h
+++ b/cmds/installd/installd.h
@@ -111,3 +111,5 @@
 int free_cache(int64_t free_size);
 int dexopt(const char *apk_path, uid_t uid, int is_public);
 int movefiles();
+int linklib(const char* target, const char* source);
+int unlinklib(const char* libPath);