#ifndef #define pattern - don't generate const

```c
#ifndef __GNUC_VA_LIST
#define __GNUC_VA_LIST
! #if defined(__svr4__) || defined(_AIX) || defined(_M_UNIX) || defined(__NetBSD__)
! typedef char *__gnuc_va_list;
! #else
! typedef void *__gnuc_va_list;
! #endif
#endif
```

This generates a `const int __GNUC_VA_LIST = 1;`.

The const is meaningless here, because it's never used as integer.

Workaround:

```yaml
macros:
exclude:
- __GNUC_VA_LIST
```

Could we detect this pattern?