A spurious "--" argument was being passed to the installer script.

Also clean-up this external command in preparation
for becoming a built-in command.

Make which_versions available in Homebrew module so
that it can be used by other commands in the future.

This allows its use in Leopard, which has Ruby 1.8.6.

- Airfoil during the install of InstantOn changes /usr/local to
  root:wheel ownership

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

This is how we do it in general in Homebrew.

Fixes Homebrew/homebrew#2709.

By forcing dylibs to have an install_name id that is the HOMEBREW_PREFIX path, ie. the symlink’s path. Stuff that links to these dylibs will use this id and thus by immune to upgrades of underlying libraries.

Thus whatever keg is "current" ie. linked, will be the library that is used by the tool.

This fix is not retroactive. So there will still be breakage for existing installations of stuff.

The fix_install step in install is moved after the link step as the symlinking
is required to determine the eventual ids for each dylib.

Before we would always make the symlink itself have a basename the same as what it pointed to.

I don’t think this breaks any of the other usages as they were working by coincidence.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Behaviour for git checkout was changed such that the update would fail because it refused to checkout files on to existing files in the working directory.

This was bad behaviour anyway, we should make efforts to keep any local modifications to the Homebrew checkout. Everything is neatly resolved if we just do a --soft reset.

Closes Homebrew/homebrew#6017.

This fixes reporting of which formulae changed in git versions where `pull`
output is not compatible.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Signed-off-by: Adam Vandenberg <flangy@gmail.com>