ART: More warnings

Enable -Wno-conversion-null, -Wredundant-decls and -Wshadow in general,
and -Wunused-but-set-parameter for GCC builds.

Change-Id: I81bbdd762213444673c65d85edae594a523836e5
diff --git a/runtime/native/dalvik_system_DexFile.cc b/runtime/native/dalvik_system_DexFile.cc
index 2d038cf..012e03e 100644
--- a/runtime/native/dalvik_system_DexFile.cc
+++ b/runtime/native/dalvik_system_DexFile.cc
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#include "dalvik_system_DexFile.h"
+
 #include <algorithm>
 #include <set>
 #include <fcntl.h>
@@ -43,13 +45,17 @@
 #include "profiler.h"
 #include "runtime.h"
 #include "scoped_thread_state_change.h"
-#include "ScopedFd.h"
 #include "ScopedLocalRef.h"
 #include "ScopedUtfChars.h"
 #include "utils.h"
 #include "well_known_classes.h"
 #include "zip_archive.h"
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wshadow"
+#include "ScopedFd.h"
+#pragma GCC diagnostic pop
+
 namespace art {
 
 // A smart pointer that provides read-only access to a Java string's UTF chars.