Introduce a new property, preserve-path, which can be used to make the

'install' rule preserve relative paths of sources when installing them.


[SVN r27587]

tools/build

@@ -1 +1 @@
-Subproject commit 332ac9b372bca958bb9b70766086e8e1a1954975
+Subproject commit 9bf995a857e0b3642795eea1abc29d9316a9bcc2