[PATCH] bitbake: Allow environment variables and ~ in bblayers

[Ed Bartosh <ed.bartosh@linux.intel.com>]

Enabled processing of environment variables in bblayers paths using
bitbake apporved_variables API.

Enabled processing of ~ if HOME environment variable is approved.

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
---
 bitbake/lib/bb/cookerdata.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/bitbake/lib/bb/cookerdata.py b/bitbake/lib/bb/cookerdata.py
index 6c11a60..05b3986 100644
--- a/bitbake/lib/bb/cookerdata.py
+++ b/bitbake/lib/bb/cookerdata.py
@@ -25,6 +25,7 @@
 import os, sys
 from functools import wraps
 import logging
+import string
 import bb
 from bb import data
 import bb.parse
@@ -269,8 +270,13 @@ class CookerDataBuilder(object):
             layers = (data.getVar('BBLAYERS', True) or "").split()
 
             data = bb.data.createCopy(data)
+            approved = dict((var, data.getVar(var, True)) \
+                                  for var in bb.utils.approved_variables())
             for layer in layers:
                 parselog.debug(2, "Adding layer %s", layer)
+                layer = string.Template(layer).safe_substitute(approved)
+                if 'HOME' in approved:
+                    layer = os.path.expanduser(layer)
                 data.setVar('LAYERDIR', layer)
                 data = parse_config_file(os.path.join(layer, "conf", "layer.conf"), data)
                 data.expandVarref('LAYERDIR')
-- 
2.1.4