Add `__truncdfsf2vfp` for ARM

src/float/trunc.rs

@@ -116,4 +116,9 @@ intrinsics! {
     pub extern "C" fn __truncdfsf2(a: f64) -> f32 {
         trunc(a)
     }
+
+    #[cfg(target_arch = "arm")]
+    pub extern "C" fn __truncdfsf2vfp(a: f64) -> f32 {
+        a as f32
+    }
 }