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, 9 insertions, 0 deletions

diff --git a/cparser/Cutil.ml b/cparser/Cutil.ml
index 25329694..cf67015a 100644
--- a/cparser/Cutil.ml
+++ b/cparser/Cutil.ml
@@ -119,6 +119,15 @@ let class_of_attribute = function
       try Hashtbl.find attr_class (normalize_attrname name)
       with Not_found -> Attr_unknown
 
+(* Name for printing an attribute *)
+
+let name_of_attribute = function
+  | AConst -> "const"
+  | AVolatile -> "volatile"
+  | ARestrict -> "restrict"
+  | AAlignas n -> "_Alignas"
+  | Attr(name, _) ->  name
+
 (* Is an attribute a ISO C standard attribute? *)
 
 let attr_is_standard = function