[ESS] R_LIBS_USER Setting

[Bill Denney]

Hi,

I use a mixture of ESS, Rgui, and RStudio for my R development in 
Windows 10.  When I install packages to the user local library in ESS, 
it installs to the R_LIBS_USER directory.  Within ESS, this works well.  
When I switch to one of the other environments (Rgui or RStudio), the 
environmental variable isn't set.

I never manually set R_LIBS_USER.  So, how does it get permanently set 
in ESS but not found in either Rgui or RStudio? And, is this something 
that I need to fix locally or is it a bug in ESS?

Thanks,

Bill