The current offset results in ELF binaries returning an `#arch` of
`:dunno`.

Also, skip the `check_binary_arches` audit on the generic OS.

There have been a few instances I've noticed that we've been silently
installing binaries built for x86_64 on ARM. There's probably more that
I haven't found yet, so it seems useful to check this with an audit.

The output format of `objdump` on Mojave is different from newer
versions of macOS, so I've adjusted the relevant audit to account for
this difference.

Co-authored-by: Rylan Polster <rslpolster@gmail.com>

1. Never install `binutils`. Instead, report an audit failure.
2. Tighten instruction check with a stricter matching strategy.

This implements the second audit discussed in #11608.

Empty files sometimes indicate that problems occurred during building or installation.

- Refuse to create bottles which have non-relocatable references to
  `HOMEBREW_LIBRARY`. This allows us to make all bottles ignore where
  `HOMEBREW_REPOSITORY` is (even those that aren't `cellar :any`).
  I cannot see any circumstances in which any bottle should link to
  anything within `HOMEBREW_REPOSITORY`.
- Remove audit that becomes unnecessary given the above change.
- Relocate references to `@HOMEBREW_LIBRARY@` but don't actually write
  any references yet. This will allow us to move to using
  `@HOMEBREW_LIBRARY` and remove all relocation of `HOMEBREW_REPOSITORY`
  in a future release (2.7.1, most likely).

Enable check_repository_references when HOMEBREW_PREFIX == HOMEBREW_REPOSITORY.

Co-authored-by: Mike McQuaid <mike@mikemcquaid.com>

Ensure that any references to HOMEBREW_REPOSITORY
are within HOMEBREW_LIBRARY.

Check plists so https://github.com/Homebrew/homebrew-services/issues/219 does not occur.

This avoids an unusual error message when Python is needed for building
(e.g., code generation) but is not used at runtime.

```
==> brew audit recode --online
Error: 1 problem in 1 formula detected
recode:
  * Packages have been installed for:

    but this formula depends on:
      Python 3.7
```

Fix various circular requirements, method redefinitions, etc.

This check is overly opinionated and leads to audit failures no one
cares to fix, so let's only run it for new formulae.