options: Allow configuring the generation of constructors.

src/options.rs

@@ -111,8 +111,8 @@ pub fn builder_from_flags<I>
             Arg::with_name("generate")
                 .long("generate")
                 .help("Generate a given kind of items, split by commas. \
-                       Valid values are \"functions\",\"types\", \"vars\" and \
-                       \"methods\".")
+                       Valid values are \"functions\",\"types\", \"vars\", \
+                       \"methods\" and \"constructors\".")
                 .takes_value(true),
             Arg::with_name("ignore-methods")
                 .long("ignore-methods")
@@ -268,6 +268,7 @@ pub fn builder_from_flags<I>
                 "types" => config.types = true,
                 "vars" => config.vars = true,
                 "methods" => config.methods = true,
+                "constructors" => config.constructors = true,
                 _ => {
                     return Err(Error::new(ErrorKind::Other,
                                           "Unknown generate item"));

tests/expectations/tests/gen-constructors.rs

@@ -0,0 +1,29 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(non_snake_case)]
+
+
+#[repr(C)]
+#[derive(Debug, Default, Copy)]
+pub struct Foo {
+    pub _address: u8,
+}
+#[test]
+fn bindgen_test_layout_Foo() {
+    assert_eq!(::std::mem::size_of::<Foo>() , 1usize , concat ! (
+               "Size of: " , stringify ! ( Foo ) ));
+    assert_eq! (::std::mem::align_of::<Foo>() , 1usize , concat ! (
+                "Alignment of " , stringify ! ( Foo ) ));
+}
+impl Clone for Foo {
+    fn clone(&self) -> Self { *self }
+}
+impl Foo {
+    #[inline]
+    pub unsafe fn new(a: ::std::os::raw::c_int) -> Self {
+        let mut __bindgen_tmp = ::std::mem::uninitialized();
+        Foo_Foo(&mut __bindgen_tmp, a);
+        __bindgen_tmp
+    }
+}

tests/headers/gen-constructors.hpp

@@ -0,0 +1,6 @@
+// bindgen-flags: --generate types,constructors
+
+class Foo {
+ public:
+  Foo(int a);
+};