Fix build errors with older GCC versions like 4.9
Fix build errors with older GCC versions like 4.9

We can add more fine grained checks for when these flags are supported so
that adding asan flags manually still has all the workarounds, but for now
compiling succesfully is more important.

tangent-opensource/coreBlackbird,tangent-opensource/coreBlackbird,tangent-opensource/coreBlackbird