R devel - Sep 2009 - DYLIB_EXT vs. SHLIB_EXT?

The graph Bioconductor package wants to compile its C code to a shared
library that is named differently from the package, to avoid conflict
with graph.dll and friends from graphviz.  So recently we tried

after: $(SHLIB)
	mv $(SHLIB) BioC_graph$(DYLIB_EXT)

and useDynLib(BioC_graph) in the NAMESPACE. This fails on Mac. We then
shifted to

after: $(SHLIB)
	mv $(SHLIB) BioC_graph$(SHLIB_EXT)

which works on all platforms we have available. Have we found a robust
solution?

Thanks for any guidance,

Martin
> sessionInfo()
R version 2.10.0 Under development (unstable) (2009-09-20 r49768)
x86_64-unknown-linux-gnu

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
 [5] LC_MONETARY=C              LC_MESSAGES=en_US.UTF-8
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
 [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base