Apparently, GMime doesn't want to create a valid address list object
for an empty string. That's annoying, but it's easy enough to test for
the empty string and avoid the problem.
InternetAddressMailbox *mailbox;
header = notmuch_message_get_header (message, "reply-to");
InternetAddressMailbox *mailbox;
header = notmuch_message_get_header (message, "reply-to");
+ if (*header == '\0')
+ return 0;
+
list = internet_address_list_parse_string (header);
if (internet_address_list_length (list) != 1)
list = internet_address_list_parse_string (header);
if (internet_address_list_length (list) != 1)