Re-add build script

Author: nhynes

.gitignore

@@ -184,7 +184,6 @@ cat.png
 *.mlmodel
 # Mac OS X
 .DS_Store
-build*
 
 # Jetbrain
 .idea

rust/build.rs

@@ -0,0 +1,47 @@
+extern crate bindgen;
+
+use std::{env, path::PathBuf};
+
+fn parse_clang_ver(raw_v: String) -> Vec<u32> {
+  raw_v
+    .split_whitespace()
+    .nth(2)
+    .unwrap()
+    .split('.')
+    .map(|v| v.parse::<u32>().unwrap())
+    .collect()
+}
+
+fn main() {
+  let clang_ver = parse_clang_ver(bindgen::clang_version().full);
+  let bindings = bindgen::Builder::default()
+    .header(concat!(
+      env!("CARGO_MANIFEST_DIR"),
+      "/../include/tvm/runtime/c_runtime_api.h"
+    ))
+    .header(concat!(
+      env!("CARGO_MANIFEST_DIR"),
+      "/../include/tvm/runtime/c_backend_api.h"
+    ))
+    .rust_target(bindgen::RustTarget::Nightly)
+    .clang_arg(concat!(
+      "-I",
+      env!("CARGO_MANIFEST_DIR"),
+      "/../dlpack/include"
+    ))
+    .clang_arg(format!("--target={}", env::var("HOST").unwrap()))
+    .clang_arg("-I/usr/include")
+    .clang_arg("-I/usr/local/include")
+    .clang_arg(format!(
+      "-I/usr/local/lib/clang/{}.{}.{}/include",
+      clang_ver[0], clang_ver[1], clang_ver[2]
+    ))
+    .layout_tests(false)
+    .generate()
+    .expect("Unable to generate bindings.");
+
+  let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
+  bindings
+    .write_to_file(out_path.join("c_runtime_api.rs"))
+    .expect("Unable to write bindings.");
+}