Don't prune cellar paths when cellar is in /opt

Fixes Homebrew/homebrew#35382.

Library/ENV/4.3/cc

@@ -26,13 +26,14 @@ end
 LOGGER = Logger.new
 
 class Cmd
-  attr_reader :brewfix, :brewtmp, :sysroot
+  attr_reader :prefix, :cellar, :tmpdir, :sysroot
 
   def initialize path, args
     @arg0 = File.basename(path).freeze
     @args = args.freeze
-    @brewfix = ENV['HOMEBREW_PREFIX']
-    @brewtmp = ENV['HOMEBREW_TEMP']
+    @prefix = ENV['HOMEBREW_PREFIX']
+    @cellar = ENV['HOMEBREW_CELLAR']
+    @tmpdir = ENV['HOMEBREW_TEMP']
     @sysroot = ENV['HOMEBREW_SDKROOT']
   end
 
@@ -199,7 +200,7 @@ class Cmd
 
   def keep? path
     case path
-    when %r{^#{Regexp.escape(brewfix)}}o, %r{^#{Regexp.escape(brewtmp)}}o
+    when %r{^#{Regexp.escape(prefix)}}o, %r{^#{Regexp.escape(cellar)}}o, %r{^#{Regexp.escape(tmpdir)}}o
       # maybe homebrew is installed to /sw or /opt/brew
       true
     when %r{^/opt}, %r{^/sw}, %r{/usr/X11}

Library/Homebrew/extend/ENV/super.rb

@@ -45,6 +45,7 @@ module Superenv
     self['HOMEBREW_OPTIMIZATION_LEVEL'] = 'Os'
     self['HOMEBREW_BREW_FILE'] = HOMEBREW_BREW_FILE.to_s
     self['HOMEBREW_PREFIX'] = HOMEBREW_PREFIX.to_s
+    self['HOMEBREW_CELLAR'] = HOMEBREW_CELLAR.to_s
     self['HOMEBREW_TEMP'] = HOMEBREW_TEMP.to_s
     self['HOMEBREW_SDKROOT'] = effective_sysroot
     self['HOMEBREW_OPTFLAGS'] = determine_optflags