RCPT TO wrong format
In case that one tries to send a mail from an email address of the form
Name <firstname.lastname@example.org>, cl-smtp does not work with certain SMTP servers, such as Google SMTP. This is because the address (w/ the name) is sent verbatim in the
RCPT TO command (e.g.
RCPT TO: <Name <email@example.com>>), which causes the SMTP server to throw an error, complaining about invalid syntax. I fixed this by stripping the name part from the address in the
RCPT TO command in case that it is present.
Since I can't open a pull request here, I'm attaching the patch herecl-smtp.patch. It makes an assumption about the email address not being malformed.