~/R/svn/R-4-1-branch/configure -C --enable-R-shlib \
--with-tcl-config=/usr/local/lib/tclConfig.sh --with-tk-config=/usr/local/lib/tkConfig.sh \
--x-includes=/opt/X11/include --x-libraries=/opt/X11/lib \
PKG_CONFIG_PATH=/opt/X11/lib/pkgconfig:/usr/local/lib/pkgconfig:/usr/lib/pkgconfig