Small performance improvements

build.rs

@@ -6,6 +6,9 @@ fn main() {
         .include(Path::new("shrooms-vb-core/core"))
         .opt_level(2)
         .flag_if_supported("-fno-strict-aliasing")
+        .define("VB_LITTLE_ENDIAN", None)
+        .define("VB_SIGNED_PROPAGATE", None)
+        .define("VB_DIV_GENERIC", None)
         .file(Path::new("shrooms-vb-core/core/vb.c"))
         .compile("vb");
 }