ltcc: exit with error code when typecheck or compilation fails

ltcc/src/main.rs

@@ -73,7 +73,7 @@ fn main() {
 
                         eprintln!("----------------------------------");
                         eprintln!("{} ({} errors)", "Typecheck failed".bright_red().bold(), type_errs.len());
-                        return;
+                        std::process::exit(-2);
                     }
                 }
 
@@ -120,6 +120,7 @@ fn main() {
                 );
     
                 eprintln!("=======\nParse Error: Abort\n");
+                std::process::exit(-1);
             }
         }
     }