metamail-environment

metamail-environment is a variable defined in `metamail.el'.
Its value is

("KEYHEADS=*" "MM_QUIET=1")

Documentation:
Environment variables passed to `metamail'.
It must be a list of strings that have the format ENVVARNAME=VALUE.
It is not expected to be altered globally by `set' or `setq'.
Instead, change its value temporary using `let' or `let*' form.