These arguments are passed to the relevant x.py invocation in all cases
anyway. As such, there is no need to separately configure them. x.py
will ignore the configuration when they are passed on the command line
anyway.
On some systems, the bash command could be available in another
directory than /bin. As such, to offer an env shebang is more
convenient.
This make sense even for docker scripts, as you can use Docker
on FreeBSD or SmartOS for example.
Mark Rousskov
Sébastien Santoro
Jessica Hamilton