error handling in initialize_globals() from cextensions can cause interpreter to segfault

The initialize_globals() function in the Storm C extensions exits early if it detects that it has been run before. Unfortunately, if it failed on the first run then it will return successfully on all subsequent runs despite not having performed necessary initialisation:

    static int
    initialize_globals(void)
    {
        static int initialized = 0;
        if (initialized)
            return 1;
        initialized = 1;
        [actual initialisation goes here]
    }

This can cause the interpreter to segfault, as demonstrated by the attached program.