Look up header dependencies on the first-output build

Ninja has special syntax to specify the first output of the given node.
E.g. it builds foo.o for foo.cc^. However, it doesn't work for
headers, as headers usually doesn't appear in the regular dependency
tree.

After this change, Ninja looks up header dependencies from .ninja_deps
to pick up a build target, so that it builds foo.o for foo.h^.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/deps_log.h b/src/deps_log.h
index 3812a28..1336078 100644
--- a/src/deps_log.h
+++ b/src/deps_log.h
@@ -86,6 +86,7 @@ struct DepsLog {
   };
   bool Load(const string& path, State* state, string* err);
   Deps* GetDeps(Node* node);
+  Node* GetFirstReverseDepsNode(Node* node);
 
   /// Rewrite the known log entries, throwing away old data.
   bool Recompact(const string& path, string* err);