class std_environment :An implementation of?config:cgi_config -> unit ->cgi_environment
cgi_environment, intended to be used
for classical CGI.
The input channel is stdin, the input environment comes from the process
environment, the output channel is stdout.
The new operator will raise Std_environment_not_found if the typical
CGI environment variables are not set.
config : The configuration to use. Default: default_config.