+static const char *clean_message_id(const char *msg_id)
+{
+ char ch;
+ const char *a, *z, *m;
+ char *n;
+ size_t len;
+
+ m = msg_id;
+ while ((ch = *m) && (isspace(ch) || (ch == '<')))
+ m++;
+ a = m;
+ z = NULL;
+ while ((ch = *m)) {
+ if (!isspace(ch) && (ch != '>'))
+ z = m;
+ m++;
+ }
+ if (!z)
+ die("insane in-reply-to: %s", msg_id);
+ if (++z == m)
+ return a;
+ len = z - a;
+ n = xmalloc(len + 1);
+ memcpy(n, a, len);
+ n[len] = 0;
+ return n;
+}
+