aubinator: rework print_help()

aubinator: rework print_help()

Rather than using platform specific methods to retrieve the program
name pass it explicitly. The function is called directly from main().

Similarly - basename comes in two versions POSIX (can modify string,
always pass a copy) and GNU (never modifies the string).

Just printout the complete program name, esp. since the program is not
meant to be installed. Thus using $basename is unlikely to work, not to
mention it is misleading.

Reported-by: Timothy Arceri <timothy.arceri@collabora.com>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Jonathan Gray <jsg@jsg.id.au>