winedbg: Sanity check the dwType field of MSVC thread naming exceptions.

programs/winedbg/gdbproxy.c

@@ -485,6 +485,8 @@ static BOOL handle_exception(struct gdb_context* gdbctx, EXCEPTION_DEBUG_INFO* e
         char name[9];
         SIZE_T read;
 
+        if (threadname->dwType != 0x1000)
+            return FALSE;
         if (threadname->dwThreadID == -1)
             thread = dbg_get_thread(gdbctx->process, gdbctx->de.dwThreadId);
         else

programs/winedbg/tgt_active.c

@@ -245,6 +245,9 @@ static DWORD dbg_handle_exception(const EXCEPTION_RECORD* rec, BOOL first_chance
         break;
     case EXCEPTION_WINE_NAME_THREAD:
         pThreadName = (const THREADNAME_INFO*)(rec->ExceptionInformation);
+
+        if (pThreadName->dwType != 0x1000)
+            return DBG_EXCEPTION_NOT_HANDLED;
         if (pThreadName->dwThreadID == -1)
             pThread = dbg_curr_thread;
         else