[PATCH] include: Define the _STGMEDIUM_UNION type for C++.

[Zebediah Figura]

This fixes a regression introduced by 732f67ed38a45911d726df8da5a68710d175ba1d.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47710
Signed-off-by: Zebediah Figura <z.figura12 at gmail.com>
---
 include/objidl.idl | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/include/objidl.idl b/include/objidl.idl
index a0ad1f6e01..a5466c3698 100644
--- a/include/objidl.idl
+++ b/include/objidl.idl
@@ -1426,8 +1426,11 @@ interface IAdviseSink : IUnknown
     default:         wireHGLOBAL hGeneric;
   } GDI_OBJECT;
 
+/* Defining the _STGMEDIUM_UNION type yields a violation of the C spec when
+ * NONAMELESSUNION is not defined, so only define it for C++. */
+cpp_quote("#ifdef __cplusplus")
   typedef struct _userSTGMEDIUM {
-    union switch(DWORD tymed) u {
+    union _STGMEDIUM_UNION switch(DWORD tymed) u {
     case TYMED_NULL:     ;
     case TYMED_MFPICT:   wireHMETAFILEPICT hMetaFilePict;
     case TYMED_ENHMF:    wireHENHMETAFILE hHEnhMetaFile;
@@ -1439,6 +1442,23 @@ interface IAdviseSink : IUnknown
     } DUMMYUNIONNAME;
     IUnknown *pUnkForRelease;
   } userSTGMEDIUM;
+cpp_quote("#else")
+cpp_quote("typedef struct _userSTGMEDIUM {")
+cpp_quote("    struct {")
+cpp_quote("        DWORD tymed;")
+cpp_quote("        union {")
+cpp_quote("            wireHMETAFILEPICT hMetaFilePict;")
+cpp_quote("            wireHENHMETAFILE hHEnhMetaFile;")
+cpp_quote("            GDI_OBJECT *hGdiHandle;")
+cpp_quote("            wireHGLOBAL hGlobal;")
+cpp_quote("            LPOLESTR lpszFileName;")
+cpp_quote("            BYTE_BLOB *pstm;")
+cpp_quote("            BYTE_BLOB *pstg;")
+cpp_quote("        } u;")
+cpp_quote("    } DUMMYUNIONNAME;")
+cpp_quote("    IUnknown *pUnkForRelease;")
+cpp_quote("} userSTGMEDIUM;")
+cpp_quote("#endif")
 
   typedef [unique] userSTGMEDIUM *wireSTGMEDIUM;
   typedef [wire_marshal(wireSTGMEDIUM)] uSTGMEDIUM STGMEDIUM;
-- 
2.24.1