I found slightly different problem running R on through mac terminal, but connecting remotely to an Ubuntu server, which prevented me from successfully installing a library.
The solution I have was finding out what "LANG" variable is used in Ubuntu terminal
Ubuntu > echo $LANG
en_US.TUF-8
I got "en_US.TUF-8" reply from Ubuntu.
In R session, however, I got "UTF-8" as the default value and it complained that LC_TYPEC Setting LC_CTYPE failed, using "C"
R> Sys.getenv("LANG")
"UTF-8"
So, I tried to change this variable in R. It worked.
R> Sys.setenv(LANG="en_US.UTF-8")