With GCC 9, some of the stdlibc++'s header files don't compile with
AspectC++ anymore. Until this is resolved, we compile with -std=c++11
although we actually use C++14 features; we need to ignore the
warnings pointing this out until AspectC++ works with these header
files.
Change-Id: If4d3c9fcbee61b7f8c6ffdf7f1ef9a641b6b6743