Don't warn about unused `brew install` arguments.

This is a step closer to better argument handling but for now just
fixes the issue in #1217 where it starts complaining about options like
`--build-from-source` being used.

1 files changed, 7 insertions, 1 deletions

diff --git a/Library/Homebrew/build_options.rb b/Library/Homebrew/build_options.rb
index edcae01f5..44b6440dc 100644
--- a/Library/Homebrew/build_options.rb
+++ b/Library/Homebrew/build_options.rb
@@ -103,7 +103,7 @@ class BuildOptions
 
   # @private
   def invalid_options
-    @args - @options
+    @args - @options - BuildOptions.formula_install_options
   end
 
   # @private
@@ -111,6 +111,12 @@ class BuildOptions
     invalid_options.map(&:flag).sort
   end
 
+  def self.formula_install_options
+    @formula_install_options ||= ARGV.formula_install_option_names.map do |option_name|
+      Option.new option_name[2..-1]
+    end
+  end
+
   private
 
   def option_defined?(name)