diff --git a/__init__.py b/__init__.py
index 5e91fcc29..40f2c6a1e 100644
--- a/__init__.py
+++ b/__init__.py
@@ -7,6 +7,9 @@
 #
 #  Copyright (C) 2007 Christoph Boehme
 #
+#  Copyright (C) 2012 Dirk Baechle
+#  Copyright (C) 2012 Eric Anderson
+#
 # This library is free software; you can redistribute it and/or
 # modify it under the terms of the GNU Lesser General Public
 # License version 2.1 as published by the Free Software Foundation.
@@ -293,8 +296,30 @@ def DoxyEmitter(target, source, env):
          tagfile = os.path.join(conf_dir, tagfile)
       targets.append(env.File(tagfile))
 
+   # don't clobber targets
+   for node in targets:
+      env.Precious(node)
+
+   # set up cleaning stuff
+   for node in targets:
+      env.Clean(node, node)
+
    return (targets, source)
 
+def generate_doxygen_commands(source, target, env, for_signature):
+
+   """Generate the doxygen command line (easy) and the post-execution
+   timestamping (harder).  The second part requires us to know which
+   directories are being built, which is why we do this as a Generator
+   (after the Emitter has run)"""
+   
+   dox_cmd = "cd ${SOURCE.dir}  &&  ${DOXYGEN} ${SOURCE.file}"
+   timestamp_cmds = ["date > %s"%(str(t)) for t in target]
+   print dox_cmd
+   print timestamp_cmds
+   return [dox_cmd] + timestamp_cmds
+   
+
 def generate(env):
    """
    Add builders and construction variables for the
@@ -308,7 +333,7 @@ def generate(env):
 
    import SCons.Builder
    doxyfile_builder = SCons.Builder.Builder(
-      action = "cd ${SOURCE.dir}  &&  ${DOXYGEN} ${SOURCE.file}",
+      generator = generate_doxygen_commands,
       emitter = DoxyEmitter,
       target_factory = env.fs.Entry,
       single_source = True,