Cygwin, MSys and Rtools can be happy together (Was: RE: [Rd] cygwin tar?)

Regarding the troubles reported by others with Cygwin and MSys, I would like
to point out to have both installed merrily such that you can

- use Cygwin for all 'normal' work inside of rxvt/xterm. 
- use MSys/MingW for one main purpose: building R packages.

For this to work, I use appropriate settings in the /home/$USER/.profile for
MSys to set its path (with the required Tools by BDR) and then change
directories into the /home/$USER for Cygwin. 

That gives transparent access to all files, sources, ... and yet as the
Cygwin.bat will not have been executed, that session is free (enough) of the
Cygwin dll to build the R packages.

I could detail this further if it helps.

Regards, Dirk

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