Glad to see the docs, but revised for the following reasons:
* define a meta-variable like `n' before using it
* typeset meta-variables specially, usually as a Racket variable
* 'processor-count' needed a `for-label' import for the hyperlink
* use @exec{} for `make install', because it's a command rather
than plain English
* although `PLT_SETUP_OPTIONS' was introduced for `-j', it makes
sense in general; revising the prose and moving to the end of
the bullet makes that more clear (but good job including the
index entry)
* used `env' so that the example command line works for more shells
bd0192d22d