[frobtads] Error compiling 1.2.3 with --enable-static-link

I found an error in src/osfrobtads.h related to vasprinf. It’s a missing include. I’ve pushed a fix for it to Git. It’s just a matter of adding:

#include <stdarg.h>

at the beginning of the file, right after the line:

#include <dirent.h>