Warn about removed warnings less shockingly

The problem here now is though that the warnings only appear when compiling verbosely. But they should thus be visible if the build fails. Or if people are hunting for problems.

Library/ENV/4.3/cc

@@ -106,6 +106,13 @@ class Cmd
         args << arg
       end
     end
+
+    rms = @args - args
+    %w{CPPFLAGS LDFLAGS CXXFLAGS CFLAGS}.each do |flag|
+      unison = ENV[flag].split(' ') & rms
+      puts "Warning! #{unison*' '} removed from #{flag.upcase} by superenv" unless unison.empty?
+    end
+
     args
   end
   def cflags
@@ -135,10 +142,6 @@ end
 ####################################################################### sanity
 abort "The build-tool has reset ENV. --lame-env required." unless ENV['HOMEBREW_BREW_FILE']
 
-%w{CPPFLAGS LDFLAGS CXXFLAGS CFLAGS}.each do |flag|
-  puts "#{flag} set but superenv running! Flags may be removed!" if ENV[flag]
-end
-
 ######################################################################### main
 cmd = Cmd.new($0, ARGV)
 exec "xcrun", cmd.tool, *cmd.args

Library/Homebrew/build.rb

@@ -85,14 +85,6 @@ def install f
     ENV.deps = keg_only_deps.map(&:to_s)
     ENV.x11 = f.requirements.detect{|rq| rq.class == X11Dependency }
     ENV.setup_build_environment
-    class << ENV
-      def []=(key, value)
-        case key when 'CFLAGS', 'CPPFLAGS', 'LDFAGS'
-          opoo "#{key} set with --env=super! Flags may not take effect!"
-        end
-        store(key, value)
-      end
-    end
   end
 
   f.recursive_requirements.each { |req| req.modify_build_environment }