>I think asprintf is useful - it replaces an ugly "malloc-realloc-snprintf-loop"...

Well, implement it yourself then. It's really not hard to live without, though. I don't know about this loop you're talking about but I just do this:

    int len = snprintf(NULL, 0, "fmt", ...);
    char *foo = malloc(len + 1);
    snprintf(foo, len, "fmt", ...);

Easy to wrap that up in your own asprintf function if you would find that useful. And in practice writing a lot of these functions is going to happen anyway when someone ports your non-portable code to another system.