= Environment variables

To resolve an environment variable, js_of_ocaml will perform the
following steps, in the given order:

* If the variable was set at compile time with the {{{--setenv VAR}}} flag, return it.
* If running nodejs and the variable is set in the process environment ({{{process.env}}}), return it.
* If the variable is set in {{{globalThis.jsoo_env}}}, return it. This can be used
  to set an environment variable inside a web-browser.
* Return Not_found