Import proc-macro-error-attr-1.0.2

Change-Id: I20e21e19335cd5a5bfccde08c22f28e530135454
diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..f2ac6a7
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,5 @@
+fn main() {
+    if version_check::is_max_version("1.36.0").unwrap_or(false) {
+        println!("cargo:rustc-cfg=always_assert_unwind");
+    }
+}