dev-cmd/bottle: fixup macOS symlink permissions.

These can be changed on macOS but not on Linux so we need to make them
consistent in both places for `all:` bottles to have consistent
checksums.

I investigated adding to `cleaner.rb` to fix these symlink permissions
on installation but it seems it already happens by default when
extracting so there's no need.

Library/Homebrew/dev-cmd/bottle.rb

@@ -399,6 +399,8 @@ module Homebrew
         keg.find do |file|
           # Set the times for reproducible bottles.
           if file.symlink?
+            # Need to make symlink permissions consistent on macOS and Linux
+            system "chmod", "-h", "0777", file if OS.mac?
             File.lutime(tab.source_modified_time, tab.source_modified_time, file)
           else
             file.utime(tab.source_modified_time, tab.source_modified_time)