Hi,

When using "gnus-summary-resend-message" (keypress "SDr") on a message
with such a header: "To: undisclosed-recipients:;" , the function stops
with an error:

--8<---------------cut here---------------start------------->8---
Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  string-match("@" nil 0)
  split-string(nil "@")
  textsec-email-address-suspicious-p(nil)
  textsec-email-address-header-suspicious-p("undisclosed-recipients:;")
  textsec-suspicious-p("undisclosed-recipients:;" email-address-header)
  message-send-mail()
  message-resend("email@address.com")
  gnus-summary-resend-message("email@address.com" nil)
  funcall-interactively(gnus-summary-resend-message "email@address.com" nil)
  call-interactively(gnus-summary-resend-message nil nil)
  command-execute(gnus-summary-resend-message)
--8<---------------cut here---------------end--------------->8---

How could this be fixed please?

TIA for any help,
-- 
           Peter