Add audit check for system "xcodebuild"

Library/Homebrew/cmd/audit.rb

@@ -296,8 +296,12 @@ class FormulaAuditor
       problem "use \"scons *args\" instead of \"system 'scons', *args\""
     end
 
-    if text =~ /system\s+['"]xcodebuild/ && text !~ /SYMROOT=/
-      problem "xcodebuild should be passed an explicit \"SYMROOT\""
+    if text =~ /system\s+['"]xcodebuild/
+      problem %{use "xcodebuild *args" instead of "system 'xcodebuild', *args"}
+    end
+
+    if text =~ /xcodebuild[ (]["'*]/ && text !~ /SYMROOT=/
+      problem %{xcodebuild should be passed an explicit "SYMROOT"}
     end
 
     if text =~ /Formula\.factory\(/