[C++] Re-generate ninja file when a file is added/removed

With this change, we store the results of file list related
commands in .kati_stamp. If one of them has been changed,
we re-generate ninja file.

Currently, this check is slow. We need to check the timestamp
of directories first like what we are doing for $(wildcard).

1 files changed, 8 insertions, 1 deletions

diff --git a/fileutil.h b/fileutil.h
index b282603..ff7b9e0 100644
--- a/fileutil.h
+++ b/fileutil.h
@@ -27,7 +27,14 @@ using namespace std;
 bool Exists(StringPiece f);
 double GetTimestamp(StringPiece f);
 
-int RunCommand(const string& shell, const string& cmd, bool redirect_stderr,
+enum struct RedirectStderr {
+  NONE,
+  STDOUT,
+  DEV_NULL,
+};
+
+int RunCommand(const string& shell, const string& cmd,
+               RedirectStderr redirect_stderr,
                string* out);
 
 void GetExecutablePath(string* path);