Bill Houle asked,
| What I would like is to munge the incoming mail and remove that
| erroneous blank line, merging the Subject back where it belongs.
:0Bfwh # egrep the body but filter the head
* ^^([^ ]+:.*$([ ].*$)*)*Subject:
| formail -X ""
The first set of brackets enclose caret, space, tab, and the second a space
and a tab. The space after the X in the action line is critical so that
procmail can give formail a null argument separately from "-X", but you may
write it as
| formail -X ''
if you prefer.