got the python-based build scripts working (for amd64)
diff --git a/aos/build/externals.gyp b/aos/build/externals.gyp
index 536cc19..8e4e637 100644
--- a/aos/build/externals.gyp
+++ b/aos/build/externals.gyp
@@ -5,8 +5,8 @@
     # TODO(brians): Would we not have to do this hackery if we named it externals_path etc?
     'externals': '<(AOS)/../output/downloaded',
     'externals_abs': '<!(readlink -f ../../output/downloaded)',
-    'compiled': '<(externals)/../compiled-<(aos_architecture)',
-    'compiled_abs': '<(externals_abs)/../compiled-<(aos_architecture)',
+    'compiled': '<(externals)/../compiled-<(ARCHITECTURE)',
+    'compiled_abs': '<(externals_abs)/../compiled-<(ARCHITECTURE)',
 
 # These versions have to be kept in sync with the ones in download_externals.sh.
     'eigen_version': '3.2.1',