Reject object-related and struct-related attributes on typedefs

This commit adds a check to reject type definitions such as
```
typedef __attribute((section "foo")) int fooint;
```
GCC and Clang also reject this as an error.

Without the check, the behavior is somewhat surprising:
```
fooint x;    // placed in section "foo"
fooint * x;  // placed in default section, attribute "foo" is ignored
```

Note that the following must be accepted:
```
typedef struct { ... } __attribute((packed)) t;
```
The "packed" attribute is correctly attached to the struct type and should not be checked.  This is achieved by using `attribute_of_type_no_expand` to get the attributes of the typedef-ed type, excluding the attributes carried by a struct/union or another typedef.

1 files changed, 2 insertions, 0 deletions

diff --git a/cparser/Cutil.mli b/cparser/Cutil.mli
index 400a6319..5a1e9af3 100644
--- a/cparser/Cutil.mli
+++ b/cparser/Cutil.mli
@@ -81,6 +81,8 @@ val class_of_attribute: attribute -> attribute_class
      have class [Attr_type].  Custom attributes have the class that
      was given to them using [declare_attribute], or [Attr_unknown]
      if not declared. *)
+val name_of_attribute: attribute -> string
+  (* Name for printing an attribute *)
 val attr_inherited_by_members: attribute -> bool
   (* Is an attribute of a composite inherited by members of the composite? *)