Use a parameter for the directory to be used by create-temporary-{file,directory}

[Mario Domenech Goulart]

Currently, create-temporary-file and create-temporary-directory use the value of the TMPDIR, TMP and TEMP environment variables to determine the directory where to create files/directories, falling back to /tmp if none of them is set.

Relying on environment variables to configure create-temporary-file and create-temporary-directory is not ideal, as changing those variables affect child processes as well. A better configuration option would be a parameter.