fancy-splash & GNU systems

[Miles Bader]

The fancy splash screen is special-cased to say "GNU Emacs is one
component of a Linux-based GNU system." system-type is `gnu/linux'.
On other system types, it says nothing.

I assume the reason for saying `Linux-based GNU system', rather than
just `GNU system' is to emphasize the linux/GNU distinction.  But on
other systems, why not just say "GNU Emacs is one component of a GNU
system."  After all, it's *always* true, even if that particular
system's only GNU program is emacs, and it may make people who's only
exposure to GNU is emacs wonder about the rest of GNU too.

-Miles