RF: Allow passing env when creating Config

bip/utils/config.py

@@ -398,7 +398,7 @@ class Config:
 
 
     # env=None - run all files through equivalent of op.expandvars
-    def __init__(self, cfgdir=None, selectors=None, overrides=None):
+    def __init__(self, cfgdir=None, env=None, selectors=None, overrides=None):
         """Create a Config object. Read configuration files from cfgdir.
 
         Selectors are applied using Config.resolve_selectors.
@@ -418,7 +418,7 @@ class Config:
 
         for fname in cfgfiles:
             log.debug('Loading settings from %s', fname)
-            settings.update(Config.load_config_file(fname, selectors))
+            settings.update(Config.load_config_file(fname, selectors, env))
 
         settings = Config.apply_overrides(settings, overrides)