--- a/cvise/utils/externalprograms.py
+++ b/cvise/utils/externalprograms.py
@@ -43,5 +43,6 @@ def find_external_programs():
 
     # Special case for clang-format
     programs['clang-format'] = '@CLANG_FORMAT_PATH@'
+    programs['unifdef'] = '@UNIFDEF@'
 
     return programs