This change fixes the path to 'nodejs' in the Sapling scripts, so that
the 'sl web' command works OOTB even if the user has a fresh `$PATH`
without node itself.
However, this is really a developer-only tool, and isn't needed just to
e.g. clone repositories. In particular, a 'fetchSapling' codepath would
not need it; therefore we make it optional, but turned on by default.
The intention is to have a 'saplingMinimal' expression which can be used
for that path.
NOTE: this does NOT add a 'saplingMinimal' expression to
all-packages.nix; that would just result in more Hydra churn, so we
avoid it for now.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
c847a43b67