frisk versus srfi-1 filter

[Kevin Ryde]

In the current cvs, I noticed the recent change to remove "filter"
from (srfi srfi-1) has broken frisk.  For instance,

        guile-tools frisk

produces

        ERROR: no binding `filter' in module (srfi srfi-1)

I guess scripts/frisk can be updated easily enough, but if an
application might be doing something similar then I wonder if srfi-1
could provide an alias for filter somehow, for compatibility.