anchor.diff:  
   nif_code_test_() ->
       {Descr, Tests} =
  -        case {find_protoc(), find_cplusplus_compiler()} of
  -            {false,_} -> {"Protoc not found, not trying to compile", []};
  -            {_,false} -> {"C++ compiler not found, not trying to compile", []};
  -            {_,_}     -> {"nif tests",
  -                          [{"Nif compiles", fun nif_compiles/0},
  -                           {"Nif encode decode", fun nif_encode_decode/0}]}
  +        case {want_nif_tests(), find_protoc(), find_cplusplus_compiler()} of
  +            {false,_,_} -> {"Protoc tests not wanted", []};
  +            {_,false,_} -> {"Protoc not found, not trying to compile", []};
  +            {_,_,false} -> {"No C++ compiler found, not trying to compile", []};
  +            {_,_,_}     -> {"nif tests",
  +                            [{"Nif compiles", fun nif_compiles/0},
  +                             {"Nif encode decode", fun nif_encode_decode/0}]}
           end,
       %% Without increased timeout, this test frequently times
       %% out on my slow laptop (1.6 GHz Atom N270)
  
positive.code:         unload_code(Module)
      end.
  
  find_cplusplus_compiler() ->
      case os:getenv("CXX") of
          false ->
  
negative.code: -include_lib("kernel/include/file.hrl").
  -include_lib("eunit/include/eunit.hrl").
  -include("../include/gpb.hrl").
  
  -export([test_nifs/1]). %% set whether to test nifs or not
  
  %% Include a bunch of tests from gpb_tests.
  %% The shared tests are for stuff that must work both
  