diff --git a/tools/gen_externs.py b/tools/gen_externs.py
index 2845502e..51c41899 100644
--- a/tools/gen_externs.py
+++ b/tools/gen_externs.py
@@ -64,7 +64,7 @@ def get_unknown_symbols(file: Path):
             elif not skip:
                 symbol += line.strip()
         symbols.add(symbol)
-        symbols.remove('')
+        if '' in symbols: symbols.remove('')
         if len(symbols) == 0:
             return []