This is a portable wrapper around Guile's built-in support for
interacting with the current environment, See Runtime Environment.
— Scheme Procedure: get-environment-variable name
Returns a string containing the value of the environment variable
given by the string name, or #f if the named
environment variable is not found. This is equivalent to
(getenv name).
— Scheme Procedure: get-environment-variables
Returns the names and values of all the environment variables as an
association list in which both the keys and the values are strings.