Commands:
--get <flag> output the requested flag to stdout.
--origin <flag> output the origin of the flag to stdout:
value is one of vendor, system, user, env.
--status output a synopsis with all parameters affecting the
program behaviour, the resulting flags and their origin.
--query like --status, but in deb822 format.
--query-features <area>
output the status of features for the given area.
--list output a list of the flags supported by the current vendor.
--export=(sh|make|cmdline|configure)
output something convenient to import the compilation
flags in a shell script, in make, or in a command line.
--dump output all compilation flags with their values.
--help show this help message.
--version show the version.
