The check for successful devtools load (has_devel) fails

Question

I am attempting to follow very clear instructions at hadley/devtools/wiki to build my first package. Using Mac OS X 10.8.1, loaded XCode 4.6.3, using R 3.0.1, loaded devtools. But has_devel() yields the error below. Please, what am I doing wrong?

> has_devel()
'/Library/Frameworks/R.framework/Resources/bin/R' --vanilla CMD SHLIB foo.c 

sh: make: command not found
Error: Command failed (1)

> traceback()
6: stop("Command failed (", status, ")", call. = FALSE)
5: system_check(r_path, options, c(r_env_vars(), env_vars), ...)
4: force(code)
3: in_dir(path, system_check(r_path, options, c(r_env_vars(), env_vars), 
       ...))
2: R("CMD SHLIB foo.c", tempdir())
1: has_devel()

Answer 1

You need to have make installed on your system. In Xcode go to Xcode -> Preferences -> Downloads and install the component named 'Command Line Tools'.