3b-1 C language incompatibility?

[Michael Aramini]

The C declarations below are compilable by at least 3 different
C compilers, but the 3b-1's C compiler complains that I am trying
to redefine object.  Is "object" a reserved word or predefined in
some other way in the 3b-1 C compiler?  If thats not the problem,
does anyone have any suggestions about what else might be wrong?

struct fixnum {
	char type;
	int count;
	int fix_dat;
};
struct symbol {
	char type;
	struct symbol *next;
	char *pname;
	union object *val;
	union object *plist;
};
struct cons {
	char type;
	int count;
	struct object *car;
	struct object *cdr;
};
union object {
	struct fixnum fix;
	struct symbol sym;
	struct cons cns;
	char type;
};