postinstall: Use CLI::Parser to parse args

Library/Homebrew/formula_installer.rb

@@ -914,13 +914,7 @@ class FormulaInstaller
       --
       #{HOMEBREW_LIBRARY_PATH}/postinstall.rb
       #{formula.path}
-    ].concat(ARGV.options_only) - ["--HEAD", "--devel"]
-
-    if formula.head?
-      args << "--HEAD"
-    elsif formula.devel?
-      args << "--devel"
-    end
+    ]
 
     Utils.safe_fork do
       if Sandbox.formula?(formula)

Library/Homebrew/postinstall.rb

@@ -6,15 +6,24 @@ require "global"
 require "debrew"
 require "fcntl"
 require "socket"
+require "cli/parser"
+
+def postinstall_args
+  Homebrew::CLI::Parser.new do
+    switch :force
+    switch :verbose
+    switch :debug
+  end
+end
 
 begin
+  postinstall_args.parse
   error_pipe = UNIXSocket.open(ENV["HOMEBREW_ERROR_PIPE"], &:recv_io)
   error_pipe.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
 
   trap("INT", old_trap)
 
-  formula = ARGV.resolved_formulae.first
-  formula.extend(Debrew::Formula) if ARGV.debug?
+  formula = Homebrew.args.resolved_formulae.first
   formula.run_post_install
 rescue Exception => e # rubocop:disable Lint/RescueException
   error_pipe.puts e.to_json