I applied a correction,

        * configure.in (SCM_I_GSC_STACK_GROWS_UP): Fix missing comma in
        AC_TRY_RUN.

This was causing downward stack systems to get the cross-compile
warning, and cross-compile to fail completely.

Incidentally, if this really must be known at configure time then it
might be better for the cross compile to be fatal, to avoid mysterious
problems.  It could advise how to force a value with a cache variable
or something.