diff --git a/Library/Homebrew/build.rb b/Library/Homebrew/build.rb
index 8b50a3b688..03ff9dac89 100644
--- a/Library/Homebrew/build.rb
+++ b/Library/Homebrew/build.rb
@@ -201,7 +201,7 @@ class Build
     # of software installs an executable that links against libstdc++
     # and dylibs against libc++, libc++-only dependencies can safely
     # link against it.
-    stdlibs = keg.detect_cxx_stdlibs :skip_executables => true
+    keg.detect_cxx_stdlibs(:skip_executables => true)
   end
 
   def fixopt f