Test for ctypes-prefix, and use-core without libstd.

tests/expectations/tests/no-std.rs

@@ -0,0 +1,23 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(non_snake_case)]
+
+#![no_std]
+mod libc { pub type c_int = i32; pub enum c_void {} }
+
+#[repr(C)]
+#[derive(Debug, Copy)]
+pub struct foo {
+    pub a: libc::c_int,
+    pub b: libc::c_int,
+    pub bar: *mut libc::c_void,
+}
+#[test]
+fn bindgen_test_layout_foo() {
+    assert_eq!(::core::mem::size_of::<foo>() , 16usize);
+    assert_eq!(::core::mem::align_of::<foo>() , 8usize);
+}
+impl Clone for foo {
+    fn clone(&self) -> Self { *self }
+}

tests/headers/no-std.h

@@ -0,0 +1,5 @@
+// bindgen-flags: --ctypes-prefix "libc" --use-core --raw-line "#![no_std]" --raw-line "mod libc { pub type c_int = i32; pub enum c_void {} }"
+struct foo {
+  int a, b;
+  void* bar;
+};