Fix build and add more debug info
    
    Fix building with gcc 5 by ignoring return-local-addr warning. The
    warning only occurs on non-JIT architectures and is safe to ignore.
    Otherwise -Werror causes the build to fail.
    
    Include additional debugging information for java class files such as
    local variables. Run tests during the build to make sure that
    information is present in the final jars.