[Rd] Notes on building a gcc toolchain for Rtools (but not multilib)

[Duncan Murdoch]

I've just uploaded a minor update (3.3.0.1957) to Rtools33, adding the 
cygpath.exe utility.  That utility converts between Windows style paths 
like D:/Rtools and Cygwin style paths like /cygdrive/d/Rtools.   It may 
be useful in configuration files if your external library expects to 
find gcc on the path, since Rtools no longer puts it there.  Assuming 
you want to use the Rtools toolchain, you can construct the path to the 
gcc directory in your Makevars.win file as

$(cygpath $(RTOOLS))gcc492_$(WIN)/bin

(where RTOOLS and WIN are macros from RHOME/etc/*/Makeconf that should 
already have been read.)

Thanks to JJ Allaire for the prompting on this.

Duncan Murdoch