[R] empty `Rscript -e "Rcpp:::LdFlags()"` prevents installation

[Ralf Goertz]

I wrote

> Hi,
> 
> sometimes packages (in this case "pbv") can't be installed on my linux
> system because in the tarball in src/Makevars there is a line like
> 
> PKG_LIBS = `$(R_HOME)/bin/Rscript -e "Rcpp:::LdFlags()"` $(LAPACK_LIBS)…
> 
> The command within the backticks doesn't return anything (i.e, no
> additional c++ libraries are needed) but because of the backticks an
> empty argument is passed to the linker which makes it fail. Using $()
> instead of the backticks solves the problem. Should this be reported
> to the package author or is it a problem common enough so that
> developer's guidelines should address this?

Sorry for the noise. Backticks were not the problem. For those
interested: I run R using the command

konsole -e R

to have it in its own terminal window. As I sometimes work on different
projects simultaneously I use 

cat("\033]0;R ",getwd(),"\007")

in my ~/.Rprofile to have the konsole window title display the working
directory. This is what the above command puts into the variable making
the linker fail. I now guard the cat command by "if (interactive())" and
the problem is gone. The reason the "$()" variant worked is probably due
to some subtle differences between the two.
<https://mywiki.wooledge.org/BashFAQ/082>