Proposal: Add an option to exclude specified binstubs

[boblail]

I have a Ruby project with that already has a bin/bundle script.

bin/bundle is essentially

#!/usr/bin/env ruby
load Gem.bin_path('bundler', 'bundle')

and it'd be easy for me to modify it to use Hermit Ruby (a smarter version of the following):

#!bin/ruby
load Gem.bin_path('bundler', 'bundle')

But if Hermit tries to upgrade Ruby, it'll fail b/c it can't overwrite bin/bundle.

I'd like to be able to tell Hermit to exclude a binstub — maybe like this:

e.g. You might run

hermit install ruby --without-bin bundle

and this would add a key to hermit.hcl:

excluded_bins = {
  "ruby": ["bundle"]
}

so that on initial install of Ruby but also on upgrades, Hermit would skip the bin/bundle stub

[kemper]

I created a branch as a POC for this feature. I'd be inclined to change the command line arg and hermit.hcl config to be exclude-bins and exclude_bins for parity (not done yet). Parking this branch for now.