anchor.diff:  
     yasm = callPackage ../development/compilers/yasm { };
   
  +
     ### DEVELOPMENT / INTERPRETERS
   
     acl2 = builderDefsPackage ../development/interpreters/acl2 {
  
positive.code: 
    tptp = callPackage ../applications/science/logic/tptp {};
  
    ### SCIENCE / ELECTRONICS
  
    eagle = callPackage_i686 ../applications/science/electronics/eagle { };
  
negative.code: 
  
    ### Helper functions.
  
    inherit lib config stdenvAdapters;
  
  