From Dmytro Katyukha <firemage.dima@gmail.com>:

It seems that ImportC does not allow to pass enums declared with typedef but without tag to function that receives enum as one of argument


## The code snippets:

```c
// testlib.c
typedef enum /*enum_test_1_t*/ {
    E_TEST_1_ITEM_1 = 1,
    E_TEST_1_ITEM_2,
} enum_test_1_t;

int some_func(enum_test_1_t val) {
    return val;
}
```

```d
//test.d
import testlib;

void main(string[] args) {
    enum_test_1_t val1 = E_TEST_1_ITEM_1;

    some_func(E_TEST_1_ITEM_1);
}
```

## Attempt to compile produce following output

```
dmd test.d testlib.c
test.d(6): Error: function `testlib.some_func(__tag2 val)` is not callable using argument types `(__anonymous)`
test.d(6):        cannot pass argument `E_TEST_1_ITEM_1` of type `__anonymous` to parameter `__tag2 val`
```