--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/waf-tools/relocation.py	Mon Sep 26 10:41:55 2011 +0100
@@ -0,0 +1,85 @@
+#! /usr/bin/env python
+# encoding: utf-8
+
+"""
+Waf 1.6
+
+Try to detect if the project directory was relocated, and if it was,
+change the node representing the project directory. Just call:
+
+ waf configure build
+
+Note that if the project directory name changes, the signatures for the tasks using
+files in that directory will change, causing a partial build.
+"""
+
+import os
+from waflib import Build, ConfigSet, Task, Utils, Errors
+from waflib.TaskGen import feature, before_method, after_method
+
+EXTRA_LOCK = '.old_srcdir'
+
+old1 = Build.BuildContext.store
+def store(self):
+	old1(self)
+	db = os.path.join(self.variant_dir, EXTRA_LOCK)
+	env = ConfigSet.ConfigSet()
+	env.SRCDIR = self.srcnode.abspath()
+	env.store(db)
+Build.BuildContext.store = store
+
+old2 = Build.BuildContext.init_dirs
+def init_dirs(self):
+
+	if not (os.path.isabs(self.top_dir) and os.path.isabs(self.out_dir)):
+		raise Errors.WafError('The project was not configured: run "waf configure" first!')
+
+	srcdir = None
+	db = os.path.join(self.variant_dir, EXTRA_LOCK)
+	env = ConfigSet.ConfigSet()
+	try:
+		env.load(db)
+		srcdir = env.SRCDIR
+	except:
+		pass
+
+	if srcdir:
+		d = self.root.find_node(srcdir)
+		if d and srcdir != self.top_dir and getattr(d, 'children', ''):
+			srcnode = self.root.make_node(self.top_dir)
+			print("relocating the source directory %r -> %r" % (srcdir, self.top_dir))
+			srcnode.children = {}
+
+			for (k, v) in d.children.items():
+				srcnode.children[k] = v
+				v.parent = srcnode
+			d.children = {}
+
+	old2(self)
+
+Build.BuildContext.init_dirs = init_dirs
+
+
+def uid(self):
+	try:
+		return self.uid_
+	except AttributeError:
+		# this is not a real hot zone, but we want to avoid surprizes here
+		m = Utils.md5()
+		up = m.update
+		up(self.__class__.__name__.encode())
+		for x in self.inputs + self.outputs:
+			up(x.path_from(x.ctx.srcnode).encode())
+		self.uid_ = m.digest()
+		return self.uid_
+Task.Task.uid = uid
+
+@feature('c', 'cxx', 'd', 'go', 'asm', 'fc', 'includes')
+@after_method('propagate_uselib_vars', 'process_source')
+def apply_incpaths(self):
+	lst = self.to_incnodes(self.to_list(getattr(self, 'includes', [])) + self.env['INCLUDES'])
+	self.includes_nodes = lst
+	bld = self.bld
+	self.env['INCPATHS'] = [x.is_child_of(bld.srcnode) and x.path_from(bld.srcnode) or x.abspath() for x in lst]
+
+

--- a/wscript	Mon Sep 26 10:34:34 2011 +0100
+++ b/wscript	Mon Sep 26 10:41:55 2011 +0100
@@ -287,6 +287,8 @@
         return None
 
 def configure(conf):
+    conf.check_tool("relocation", ["waf-tools"])
+
     # attach some extra methods
     conf.check_nonfatal = types.MethodType(_check_nonfatal, conf)
     conf.check_compilation_flag = types.MethodType(_check_compilation_flag, conf)