Increasing narc.ATTACHMENT name length from 64 is not simple.
Several places had hard-coded 63 or 64.
Changed h.narc to add define ATT_FLEN to narc and use for name.
Changed attach trunc_msg to add limit parameter.
Changed the following from using 63 or 64 or sizeof to ATT_FLEN...
attach.attach_menu_handler()
attach.text_mime_content_type().
attach.attach_create(). Also truncated before adding MIME/PC extension
text.text_interpret_attachment().
text.text_interpret_article().
Changed reply.make_legal_fname() from 64 to 255, to avoid any limiting of saved filenames.
Then changed h.narc ATT_FLEN from 64 to 80.
SHOULD be overkill, but not for some Word users.
Bumped c.wimp version to v3.21a (13 Feb 2024)
Updated Help.
