libs/vkd3d: Introduce vkd3d_create_device().

We need to pass additional parameters to libvkd3d during initialization.

include/vkd3d.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2016 Józef Kucia for CodeWeavers
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef __VKD3D_H
+#define __VKD3D_H
+
+#include "vkd3d_windows.h"
+#include "d3d12.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif  /* __cplusplus */
+
+struct vkd3d_device_create_info
+{
+    D3D_FEATURE_LEVEL minimum_feature_level;
+};
+
+HRESULT WINAPI vkd3d_create_device(const struct vkd3d_device_create_info *create_info,
+        REFIID riid, void **device);
+
+#ifdef __cplusplus
+}
+#endif  /* __cplusplus */
+
+#endif  /* __VKD3D_H */