MFC r272974,272976:

Add ${name}_env and ${name}_prepend. ${name}_env is an argument list which
will be passed to env(1). ${name}_prepend is simply prepended to the command
line for $command.

MFC r272974,272976:

Add ${name}_env and ${name}_prepend. ${name}_env is an argument list which
will be passed to env(1). ${name}_prepend is simply prepended to the command
line for $command.