Make gperftools build with c++20.

Change-Id: I2a5e614a6da7cdfd4d1af4d47c9d693c0172df36
Signed-off-by: Tyler Chatow <tchatow@gmail.com>
diff --git a/third_party/gperftools/BUILD b/third_party/gperftools/BUILD
index 2022ee6..14ac821 100644
--- a/third_party/gperftools/BUILD
+++ b/third_party/gperftools/BUILD
@@ -32,6 +32,8 @@
     "-Wno-switch-enum",
     "-Wno-error=cast-align",
     "-Wno-error=cast-qual",
+    "-Wno-deprecated-volatile",
+    "-Wno-cast-qual",
 
     # //build_tests:tcmalloc_build_test relies on this.
     "-DENABLE_LARGE_ALLOC_REPORT=1",