target name not known until configure time

[mcmahill]

how can I get someting like this to work?  The suffix depends on the
operating system and hardware platform.  That requirement is set by
something out of my control.  I get complaints from automake about the
constructs I've used in the pipestage_${MEXSFX}_SOURCES line.

Thanks
-Dan


MEXSFX=@MEXSFX@
MEX=@MEX@

libexec_PROGRAMS=       pipestage.${MEXSFX}
pipestage_${MEXSFX}_SOURCES=   pipestage.c

SUFFIXES = .c .${MEXSFX}

.c.${MEXSFX} :
        $(MEX) $*.c