lib: remove enum names from typedefs

lib: remove enum names from typedefs

There are some enum typedefs with the enum name:

    typedef enum _name_t { ... } name_t;

We don't need or use the enum names _name_t for anything, and not all
of the enum typedefs have them. We have the typedefs specifically to
use the typedef name.

Use the anonymous enum in the typedefs:

    typedef enum { ... } name_t;