diff --git a/pre-upload.py b/pre-upload.py
index 4c6b783..8e9ca14 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -457,7 +457,7 @@
   MAX_LEN = 80
   SKIP_REGEXP = re.compile('|'.join([
       r'https?://',
-      r'^#\s*(define|include|import|pragma|if|endif)\b']))
+      r'^#\s*(define|include|import|pragma|if|ifndef|endif)\b']))
 
   included, excluded = _parse_common_inclusion_options(options)
   files = _filter_files(_get_affected_files(commit),