Bug 1402012 - Create config.statusd directory; r=glandium

The config.statusd directory is created alongside config.status, which
contains the same information but is split across many files instead of
all in a single file. This allows the build system to track dependencies
on individual configure values.

MozReview-Commit-ID: 2DbwKCJuNSX

configure.py

@@ -17,6 +17,7 @@ sys.path.insert(0, os.path.join(base_dir, 'python', 'mozbuild'))
 from mozbuild.configure import ConfigureSandbox
 from mozbuild.makeutil import Makefile
 from mozbuild.pythonutil import iter_modules_in_path
+from mozbuild.backend.configenvironment import PartialConfigEnvironment
 from mozbuild.util import (
     indented_repr,
     encode,
@@ -90,6 +91,9 @@ def config_status(config):
                     config_status(**args)
             '''))
 
+    partial_config = PartialConfigEnvironment(config['TOPOBJDIR'])
+    partial_config.write_vars(sanitized_config)
+
     # Write out a depfile so Make knows to re-run configure when relevant Python
     # changes.
     mk = Makefile()