Is it safe to use an enum in a bit field?

Say, I've got the following struct:

typedef struct my_struct{
    unsigned long       a;
    unsigned long       b;
    char*               c;
    unsigned int        d1  :1;
    unsigned int        d2  :4;
    unsigned int        d3  :4;
    unsigned int        d4  :23;
} my_type, *p_type;

The field d3 is currently defined by #defines that reach from 0x00 until 0x0D.

Actually, d3 is an enumeration. So it's tempting to go ahead and replace

    unsigned int        d3  :4;

by

    my_enum             d3  :4;

Is this safe/allowed?

The code has to compile with various

• compilers (GCC, Visual Studio, embedded stuff)
• platforms (Win32, Linux, embedded stuff)
• configurations (compile as C, compile as C++)

Obviously, I could leave the definition of d3 as it is and use the enum in my code, assign it to d3 and so on but that's not going to work with C++.