Add support for local packages through 'file://' pseudo-protocol

This can be used this way :

<pkg>_VERSION = 42
<pkg>_SITE = file:///some/local/directory
<pkg>_SOURCE = mypkg-$(<pkg>_VERSION).tar.bz2

Can be useful to integrate a home-made project or for testing purposes.
The default command to retrieve files is 'cp' but 'rsync' could also be used.
Through sshfs, it should also be possible to get non-public remote files on a
ssh server.

[ Thomas Petazzoni: use $(PKG)_SITE and $(PKG)_SOURCE variables
  instead of $(1) and $(2) ]
[ Peter: don't append $(QUIET), cp doesn't handle -q]
Signed-off-by: David Wagner <david.wagner@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
diff --git a/Config.in b/Config.in
index 3aa3ad8..0cf4d49 100644
--- a/Config.in
+++ b/Config.in
@@ -32,6 +32,10 @@
 	string "Git command"
 	default "git"
 
+config BR2_LOCALFILES
+	string "Local files retrieval command"
+	default "cp"
+
 config BR2_ZCAT
 	string "zcat command"
 	default "gzip -d -c"