add prune-gcc

cmd/prune-gcc.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "formula"
+require "open-uri"
+
+module Homebrew
+  module_function
+
+  def prune_gcc
+    gcc = Formula["gcc"]
+
+    gcc.prefix.children.each do |f|
+      rm_rf f unless f.to_s.end_with? "lib"
+    end
+
+    (gcc.lib/"gcc").children.each do |f|
+      rm_rf f unless f.to_s.end_with? "current"
+    end
+
+    (gcc.lib/"gcc/current").children.each do |f|
+      rm_rf f unless f.to_s.end_with? ".dylib"
+    end
+  end
+end