diff --git a/build.rs b/build.rs
index efc0667..c05769f 100644
--- a/build.rs
+++ b/build.rs
@@ -10,6 +10,8 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     LexerBuilder::new()
         .rule_ids_map(lex_rule_ids_map)
         .process_file_in_src("vm/obj/syn/lexer.l")?;
+    LexerBuilder::<u32>::new()
+        .process_file_in_src("vm/obj/syn/preprocessor.l")?;
     rerun_except(&[
         "examples/*.asm",
         "tests/*.asm",