importC error: _Builtin_stddef

[Dakota]

get this error:


```sh
In file included from /llvm/lib/clang/18/include/stddef.h:77,
                  from /usr/include/time.h:29,
                  from /llvm/include/clang-c/CXFile.h:17,
                  from /llvm/include/clang-c/CXSourceLocation.h:17,
                  from /llvm/include/clang-c/CXDiagnostic.h:17,
                  from /llvm/include/clang-c/Index.h:20,
                  from /opt/d/D/c2d/src/c2di.c:1:
/llvm/lib/clang/18/include/__stddef_size_t.h:15:50: error: 
missing binary operator before token "("
    15 |     (__has_feature(modules) && 
!__building_module(_Builtin_stddef))
       |                                                  ^
In file included from /llvm/lib/clang/18/include/stddef.h:92:
/llvm/lib/clang/18/include/__stddef_null.h:10:41: error: missing 
binary operator before token "("
    10 | #if !defined(NULL) || !__building_module(_Builtin_stddef)

```