dovecot.m4: Export also LIBDOVECOT_IMAP_INCLUDE
dovecot.m4: Export also LIBDOVECOT_IMAP_INCLUDE

jkerihuel/dovecot,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jwm/dovecot-notmuch