Uploading a package is an irreversible operation. It's not even about
accidentally leaking your secret sauce to the internet. You could upload
a package to snow-fort.org by accident and pullute the package name
space [1].
So let's ask the user first before going ahead uploading stuff. We only
ask once even if we're going to upload a dozen packages, so it's not
that annoying. The target repo is also shown in case you want to upload
to a custom repo and want to make sure it does so.
[1] I did (while attempting to uploading to a local snow-fort instance
during testing). I guess `(chibi snow commands)` is forever mine
now.
Tested with gauche. It's mostly about not importing (chibi test)
unconditionally, and importing (scheme write). And in one case I need to
exclude some tests because gauche catches invalid call forms at compile
time. I'm not sure if that can be caught...
The procedure parameter name could equally well be changed from `id` to
`proc`. Not sure which approach is more suitable - here, I chose to
stick to the original procedure signature.
Currently a package's cond-expand contains the symbol of the target
implementation and optionally more from config file. Execute a
command (once) on target implementation to add their full feature list,
making it available for each package to use.
All of these Schemes are tested. Larceny is just too annoying to get the
feature list (no one-liner, and it could take a while) so Larceny stays
the current behavior.
There is a small unrelated change here: the gosh command to get
version. We don't need to call (exit), if stdin is closed properly (it
should) then gosh should exit regardless.
