Support more configurability in GN toolchains

tools/gn/config_values_extractors_unittest.cc

Index: tools/gn/config_values_extractors_unittest.cc
diff --git a/tools/gn/config_values_extractors_unittest.cc b/tools/gn/config_values_extractors_unittest.cc
index 0076b9e1cca8bbe0427901d876ef1ae86911f8d8..a4082265cebb94bfd98fc835465dfbd8ccf659a2 100644
--- a/tools/gn/config_values_extractors_unittest.cc
+++ b/tools/gn/config_values_extractors_unittest.cc
@@ -45,6 +45,7 @@ TEST(ConfigValuesExtractors, IncludeOrdering) {
 
   Target dep2(setup.settings(), Label(SourceDir("//dep2/"), "dep2"));
   dep2.set_output_type(Target::SOURCE_SET);
+  dep2.SetToolchain(setup.toolchain());
   dep2.all_dependent_configs().push_back(LabelConfigPair(&dep2_all));
   dep2.direct_dependent_configs().push_back(LabelConfigPair(&dep2_direct));
 
@@ -60,6 +61,7 @@ TEST(ConfigValuesExtractors, IncludeOrdering) {
 
   Target dep1(setup.settings(), Label(SourceDir("//dep1/"), "dep1"));
   dep1.set_output_type(Target::SOURCE_SET);
+  dep1.SetToolchain(setup.toolchain());
   dep1.all_dependent_configs().push_back(LabelConfigPair(&dep1_all));
   dep1.direct_dependent_configs().push_back(LabelConfigPair(&dep1_direct));
   dep1.deps().push_back(LabelTargetPair(&dep2));
@@ -85,6 +87,7 @@ TEST(ConfigValuesExtractors, IncludeOrdering) {
 
   Target target(setup.settings(), Label(SourceDir("//target/"), "target"));
   target.set_output_type(Target::SOURCE_SET);
+  target.SetToolchain(setup.toolchain());
   target.all_dependent_configs().push_back(LabelConfigPair(&target_all));
   target.direct_dependent_configs().push_back(LabelConfigPair(&target_direct));
   target.configs().push_back(LabelConfigPair(&target_config));