add option to use DST structs for flex arrays

bindgen-cli/options.rs

@@ -406,6 +406,9 @@ struct BindgenCommand {
     /// Set path for temporary files generated by fallback for clang macro parsing.
     #[arg(long)]
     clang_macro_fallback_build_dir: Option<PathBuf>,
+    /// Use DSTs to represent structures with flexible array members.
+    #[arg(long)]
+    flexarray_dst: bool,
     /// Derive custom traits on any kind of type. The CUSTOM value must be of the shape REGEX=DERIVE where DERIVE is a coma-separated list of derive macros.
     #[arg(long, value_name = "CUSTOM", value_parser = parse_custom_derive)]
     with_derive_custom: Vec<(Vec<String>, String)>,
@@ -562,6 +565,7 @@ where
         wrap_unsafe_ops,
         clang_macro_fallback,
         clang_macro_fallback_build_dir,
+        flexarray_dst,
         with_derive_custom,
         with_derive_custom_struct,
         with_derive_custom_enum,
@@ -1039,6 +1043,10 @@ where
         builder = builder.clang_macro_fallback_build_dir(path);
     }
 
+    if flexarray_dst {
+        builder = builder.flexarray_dst(true);
+    }
+
     #[derive(Debug)]
     struct CustomDeriveCallback {
         derives: Vec<String>,