tuntap: recommend upstream signed binary.

We have an upstream signed binary available! Big big love to Mattias
for this.

This PR converts all the existing tuntap dependencies into
binary-friendly tuntap dependencies, and adds a tuntap dependency to
requirements to look for the kexts.

Closes Homebrew/homebrew#33894.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Library/Homebrew/dependency_collector.rb

@@ -120,6 +120,7 @@ class DependencyCollector
     when :python3    then Python3Dependency.new(tags)
     when :java       then JavaDependency.new(tags)
     when :osxfuse    then OsxfuseDependency.new(tags)
+    when :tuntap     then TuntapDependency.new(tags)
     # Tiger's ld is too old to properly link some software
     when :ld64       then LD64Dependency.new if MacOS.version < :leopard
     when :ant        then ant_dep(spec, tags)

Library/Homebrew/requirements.rb

@@ -6,6 +6,7 @@ require 'requirements/maximum_macos_requirement'
 require 'requirements/mpi_dependency'
 require 'requirements/osxfuse_dependency'
 require 'requirements/python_dependency'
+require 'requirements/tuntap_dependency'
 require 'requirements/unsigned_kext_requirement'
 require 'requirements/x11_dependency'
 

Library/Homebrew/requirements/tuntap_dependency.rb

@@ -0,0 +1,13 @@
+require "requirement"
+
+class TuntapDependency < Requirement
+  fatal true
+  default_formula "tuntap"
+  satisfy { self.class.binary_tuntap_installed? || Formula["tuntap"].installed? }
+
+  def self.binary_tuntap_installed?
+    File.exist?("/Library/Extensions/tun.kext") && File.exist?("/Library/Extensions/tap.kext")
+    File.exist?("/Library/LaunchDaemons/net.sf.tuntaposx.tun.plist")
+    File.exist?("/Library/LaunchDaemons/net.sf.tuntaposx.tap.plist")
+  end
+end