extern char *__progname; // This is where glibc stashes argv[0].
len = snprintf(buf, sizeof(buf), "%s:%d:%s(): tid %d at %d.%09d: ",
__progname, line, func, gettid(),
extern char *__progname; // This is where glibc stashes argv[0].
len = snprintf(buf, sizeof(buf), "%s:%d:%s(): tid %d at %d.%09d: ",
__progname, line, func, gettid(),