Implement `Clone` for `Builder`

This is done by moving all the remaining `Builder` state into
`BindgenOptions` so any internal logic that affects `Builder` state only
runs once the builder is consumed by `Builder::generate`:

- move `input_headers` to `BindgenOptions`.
- move `input_header_contents` to `BindgenOptions`.
- derive `Clone` for `Builder`.

1 files changed, 1 insertions, 1 deletions

diff --git a/bindgen/clang.rs b/bindgen/clang.rs
index ea505c87..e5113391 100644
--- a/bindgen/clang.rs
+++ b/bindgen/clang.rs
@@ -1823,7 +1823,7 @@ pub struct UnsavedFile {
 
 impl UnsavedFile {
     /// Construct a new unsaved file with the given `name` and `contents`.
-    pub fn new(name: &str, contents: &str) -> UnsavedFile {
+    pub fn new(name: String, contents: String) -> UnsavedFile {
         let name = CString::new(name).unwrap();
         let contents = CString::new(contents).unwrap();
         let x = CXUnsavedFile {