Fix bugs in --clang-macro-fallback

This commit resolves a bug where -include was not respected and a bug
where -MMD was passed to the fallback translation unit which would cause
the dependency file to be overwritten with useless information about
temporary files.

bindgen/ir/context.rs

@@ -2104,7 +2104,8 @@ If you encounter an error missing from this list, please file an issue or a PR!"
                     .iter()
                     .filter(|next| {
                         !self.options.input_headers.contains(next) &&
-                            next.as_ref() != "-include"
+                            !next.contains("-MD") &&
+                            !next.contains("-MMD")
                     })
                     .cloned(),
             );
@@ -2124,11 +2125,11 @@ If you encounter an error missing from this list, please file an issue or a PR!"
             c_args.extend(
                 self.options
                     .clang_args
-                    .clone()
                     .iter()
                     .filter(|next| {
                         !self.options.input_headers.contains(next) &&
-                            next.as_ref() != "-include"
+                            !next.contains("-MD") &&
+                            !next.contains("-MMD")
                     })
                     .cloned(),
             );