GN: Makes GN output deterministic

tools/gn/target.cc

Index: tools/gn/target.cc
diff --git a/tools/gn/target.cc b/tools/gn/target.cc
index 4a93abc240cd36655d24a9ec8e0a9d52749e8543..e6a14c6e4d67200ad7f328e3b6eff5f299ab516f 100644
--- a/tools/gn/target.cc
+++ b/tools/gn/target.cc
@@ -9,6 +9,7 @@
 #include "base/strings/stringprintf.h"
 #include "tools/gn/config_values_extractors.h"
 #include "tools/gn/deps_iterator.h"
+#include "tools/gn/dereference_comparator.h"
 #include "tools/gn/filesystem_utils.h"
 #include "tools/gn/scheduler.h"
 #include "tools/gn/substitution_writer.h"
@@ -70,7 +71,7 @@ Err MakeStaticLibDepsError(const Target* from, const Target* to) {
 bool EnsureFileIsGeneratedByDependency(const Target* target,
                                        const OutputFile& file,
                                        bool check_private_deps,
-                                       std::set<const Target*>* seen_targets) {
+                                       PointerSet<const Target>* seen_targets) {
   if (seen_targets->find(target) != seen_targets->end())
     return false;  // Already checked this one and it's not found.
   seen_targets->insert(target);
@@ -548,7 +549,11 @@ void Target::CheckSourceGenerated(const SourceFile& source) const {
   // the list of files written by the GN build itself (often response files)
   // can be filtered out of this list.
   OutputFile out_file(settings()->build_settings(), source);
-  std::set<const Target*> seen_targets;
+  PointerSet<const Target> seen_targets;
   if (!EnsureFileIsGeneratedByDependency(this, out_file, true, &seen_targets))
     g_scheduler->AddUnknownGeneratedInput(this, source);
 }
+
+bool Target::operator<(const Target& other) const {
+  return label() < other.label();
+}