Fix for when std::os::raw::c_char is u8 (armv7)
diff --git a/tests/test.rs b/tests/test.rs
index ddf8f70..91bd25e 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -141,7 +141,7 @@
         }
         let failure = unsafe { cxx_run_test() };
         if !failure.is_null() {
-            let msg = unsafe { CStr::from_ptr(failure) };
+            let msg = unsafe { CStr::from_ptr(failure as *mut std::os::raw::c_char) };
             eprintln!("{}", msg.to_string_lossy());
         }
     }