doc: conf.py: make sure west is importable from Python

We need this to be able to pull in its API documentation.

This will need modifications when multi-repo support is available, in
order to get the imports from the independent West repo, but for now
just use the copy in Zephyr.

Signed-off-by: Marti Bolivar <marti@opensourcefoundries.com>

doc/conf.py

@@ -15,9 +15,16 @@
 import sys
 import os
 
+if "ZEPHYR_BASE" not in os.environ:
+    sys.stderr.write("$ZEPHYR_BASE environment variable undefined.\n")
+    exit(1)
+ZEPHYR_BASE = os.environ["ZEPHYR_BASE"]
+
 # Add the 'extensions' directory to sys.path, to enable finding Sphinx
 # extensions within.
 sys.path.insert(0, os.path.join(os.path.abspath('.'), 'extensions'))
+# Also add west, to be able to pull in its API docs.
+sys.path.append(os.path.abspath(os.path.join(ZEPHYR_BASE, 'scripts', 'meta')))
 
 # -- General configuration ------------------------------------------------
 
@@ -52,11 +59,6 @@ project = u'Zephyr Project'
 copyright = u'2015-2017 Zephyr Project members and individual contributors.'
 author = u'many'
 
-if "ZEPHYR_BASE" not in os.environ:
-    sys.stderr.write("$ZEPHYR_BASE environment variable undefined.\n")
-    exit(1)
-ZEPHYR_BASE = os.environ["ZEPHYR_BASE"]
-
 # The following code tries to extract the information by reading the Makefile,
 # when Sphinx is run directly (e.g. by Read the Docs).
 try: