fixed copy elision error in clang 3.8

Change-Id: I31f95667c309c80ade1289f0923e261e51bfa3a1
diff --git a/third_party/gperftools/BUILD b/third_party/gperftools/BUILD
index 4fa332f..7676131 100644
--- a/third_party/gperftools/BUILD
+++ b/third_party/gperftools/BUILD
@@ -208,6 +208,7 @@
   ],
   copts = common_copts + [
     '-fno-builtin',
+    '-Wno-mismatched-new-delete',
   ],
   size = 'small',
 )