Adds support for nested structs and unions.

parser.rs
- Adds detection of nested composite fields so that they can be handled
  specially during generation (see visit_composite).
- Changes to manual recursion through Clang's cursors so that top-level
  and nested composites can be handled separately.

gen.rs
- Improves generation for nested composite types.
- Unifies handling of structs and unions somewhat.

types.rs
- Adds CompKind to distinguish between structs and unions.
- Updates CompInfo to use CompKind rather than a bool.

1 files changed, 6 insertions, 0 deletions

diff --git a/tests/headers/struct_with_struct.h b/tests/headers/struct_with_struct.h
new file mode 100644
index 00000000..78b1cc81
--- /dev/null
+++ b/tests/headers/struct_with_struct.h
@@ -0,0 +1,6 @@
+struct foo {
+    struct {
+        unsigned int x;
+        unsigned int y;
+    } bar;
+};