[mew-int 01889] Picking of expressions with spaces doesn't work in 4.x

[Bernhard Heidegger]

Hi,

I'm using mew since years on a rather ancient Redhat 7.2 box with
xemacs 21.1.14 (Mule).

In mew versions up to 3.3rc1 it was possible to pick
subject=****Maybe SPAM****
(or use an equivalent virtual mode)

With mew 4.x (now on 4.1rc2) I get the error message:
"Variable binding depth exceeds max-specpdl-size"

It seems the parsing algorithm has changed and doesn't work with
spaces anymore (even spaces around operators like
from=sombody & subject=something
don't work)

The shortened backtrace:
Signaling: (error "Variable binding depth exceeds max-specpdl-size")
  mew-pick-macro-expand-string(" SPAM****")
[removed many duplicate lines]
  mew-pick-macro-expand-string(" SPAM****")
  mew-pick-macro-expand-string("subject=****Maybe SPAM****")
  mew-input-pick-pattern()
  mew-summary-virtual-with-internal()
  mew-summary-virtual(nil)
  call-interactively(mew-summary-virtual)

I've also tried to quote the terms but nothing seems to work. Can you
shed some light on this?

Thanks,
Bernhard