diff -urBwbE mingw-w64-headers-1.0b.20100730/ddk/include/ddk/wdm.h mingw-w64-headers-1.0b.20100730/ddk/include/ddk/wdm.h
--- mingw-w64-headers-1.0b.20100730/ddk/include/ddk/wdm.h	2010-07-27 11:14:13.000000000 +0200
+++ mingw-w64-headers-1.0b.20100730/ddk/include/ddk/wdm.h	2010-08-14 15:36:21.000000000 +0200
@@ -56,7 +56,11 @@
 #endif /* _MAC */
 
 #ifndef _KTMTYPES_
+#ifdef _MSC_VER
 typedef GUID UOW, *PUOW;
+#else
+typedef GUID *PUOW;
+#endif
 #endif
 
 typedef GUID *PGUID;
@@ -14867,10 +14871,10 @@
 } ENLISTMENT_INFORMATION_CLASS;
 
 typedef struct _TRANSACTION_LIST_ENTRY {
-#if defined(__cplusplus)
-  ::UOW UOW;
-#else
+#ifdef _MSC_VER
   UOW UOW;
+#else
+  GUID UOW;
 #endif
 } TRANSACTION_LIST_ENTRY, *PTRANSACTION_LIST_ENTRY;
 
diff -urBwbE mingw-w64-headers-1.0b.20100730/include/ktmtypes.h mingw-w64-headers-1.0b.20100730/include/ktmtypes.h
--- mingw-w64-headers-1.0b.20100730/include/ktmtypes.h	2010-07-08 11:25:17.000000000 +0200
+++ mingw-w64-headers-1.0b.20100730/include/ktmtypes.h	2010-08-14 15:43:00.000000000 +0200
@@ -92,7 +92,11 @@
 #define MAX_RESOURCEMANAGER_DESCRIPTION_LENGTH  64
 
 #ifndef _WDMDDK_
+#ifdef _MSC_VER
 typedef GUID UOW, *PUOW;
+#else
+typedef GUID *PUOW;
+#endif
 #endif
 
 typedef GUID CRM_PROTOCOL_ID, *PCRM_PROTOCOL_ID;
@@ -108,10 +112,10 @@
 
 typedef struct _TRANSACTION_NOTIFICATION_RECOVERY_ARGUMENT {
   GUID EnlistmentId;
-#if defined(__cplusplus)
-  ::UOW UOW;
-#else
+#ifdef _MSC_VER
   UOW UOW;
+#else
+  GUID UOW;
 #endif
 } TRANSACTION_NOTIFICATION_RECOVERY_ARGUMENT, *PTRANSACTION_NOTIFICATION_RECOVERY_ARGUMENT;
 
@@ -126,7 +130,11 @@
 
 typedef struct _TRANSACTION_NOTIFICATION_PROPAGATE_ARGUMENT {
   ULONG PropagationCookie;
+#ifdef _MSC_VER
+  UOW UOW;
+#else
   GUID UOW;
+#endif
   GUID TmIdentity;
   ULONG BufferLength;
 } TRANSACTION_NOTIFICATION_PROPAGATE_ARGUMENT, *PTRANSACTION_NOTIFICATION_PROPAGATE_ARGUMENT,
@@ -134,7 +142,11 @@
 
 typedef struct _TRANSACTION_NOTIFICATION_MARSHAL_ARGUMENT {
   ULONG MarshalCookie;
+#ifdef _MSC_VER
+  UOW UOW;
+#else
   GUID UOW;
+#endif
 } TRANSACTION_NOTIFICATION_MARSHAL_ARGUMENT, *PTRANSACTION_NOTIFICATION_MARSHAL_ARGUMENT;
 
 typedef struct _KCRM_MARSHAL_HEADER {
@@ -145,10 +157,10 @@
 } KCRM_MARSHAL_HEADER, *PKCRM_MARSHAL_HEADER, *RESTRICTED_POINTER PRKCRM_MARSHAL_HEADER;
 
 typedef struct _KCRM_TRANSACTION_BLOB {
-#if defined(__cplusplus)
-  ::UOW UOW;
-#else
+#ifdef _MSC_VER
   UOW UOW;
+#else
+  GUID UOW;
 #endif
   GUID TmIdentity;
   ULONG IsolationLevel;