[plt-scheme] drscheme language for r5rs + specific srfis

Is there an easy way to have DrScheme give me a language that only has
R5RS plus specific SRFIs?

Immediate desire is to use DrScheme to detect portability problems in a
program that should use only R5RS plus SRFI-6 (string ports).

I could write my own extension to the "R5RS" DrScheme language, or
define an `r5rs-srfi6' language for the module system and temporarily
wrap my program in a module.  Is there an easier way?

Ideally, I could select the "R5RS with SRFIs" language from a DrScheme
dialog, and then selectively check which SRFIs I wanted.  (Incidentally,
this would be useful for developing and testing different cases of
SRFI-0 `cond-expand' in portable Scheme code.)

-- 
                                             http://www.neilvandyke.org/