cleanup dev tree after build, fixes #806

tools/build/build.py

@@ -85,7 +85,13 @@ def build_oxjs(downloads=False, geo=False):
                 link_target = target.replace(build_path, dev_path)
                 if not is_jquery_min:
                     write_link(link_source, link_target)
-
+    # remove dangling links from dev tree that might
+    # be left over from renames or removed files
+    for path, dirnames, filenames in os.walk(dev_path):
+        for f in filenames:
+            f = os.path.join(path, f)
+            if os.path.islink(f) and not os.path.exists(f):
+                os.unlink(f)
     # Ox.js
     filenames = [
         [