'WebServices.h' and 'clang-cl' error

[gvanem]

Compiling a C or C++ file that includes <WebServices.h> in my Winkit SDK,
generates these errors using clang-cl (ver. 19.1):

In file included from objects/PurchaseOrder.wsdl.c:3:
f:\gv\WinKit\Include\10.0.22621.0\um\WebServices.h(695,1): error: use of empty enum
  695 | } WS_XML_BUFFER_PROPERTY_ID;
      | ^
f:\gv\WinKit\Include\10.0.22621.0\um\WebServices.h(1603,1): error: use of empty enum
 1603 | } WS_SECURITY_ALGORITHM_PROPERTY_ID;
      | ^
2 errors generated.

for these empty enums:

typedef enum
{
} WS_XML_BUFFER_PROPERTY_ID;  // line 695
...
typedef enum
{
} WS_SECURITY_ALGORITHM_PROPERTY_ID;  // line 1603

(The .c-file in question that I used was the generated PurchaseOrder.wsdl.c in this Windows Classic Samples project).

What is the purpose of an empty enum?