[build] Copy uefi headers into project

Eventually the UEFI headers should be brought in from their own project,
but for now, like the other projects under external/, these are being
copied into this repository.

Tags: boot uefi

external/uefi/protos/device_path.h

@@ -0,0 +1,30 @@
+#pragma once
+#ifndef _uefi_protos_device_path_h_
+#define _uefi_protos_device_path_h_
+
+// This file was auto generated by the j6-uefi-headers project. Please see
+// https://github.com/justinian/j6-uefi-headers for more information.
+
+#include <uefi/guid.h>
+#include <uefi/types.h>
+
+namespace uefi {
+namespace protos {
+struct device_path;
+
+struct device_path
+{
+    static constexpr uefi::guid guid{ 0x09576e91,0x6d3f,0x11d2,{0x8e,0x39,0x00,0xa0,0xc9,0x69,0x72,0x3b} };
+
+    uint8_t type;
+    uint8_t sub_type;
+    uint16_t length;
+
+protected:
+public:
+};
+
+} // namespace protos
+} // namespace uefi
+
+#endif // _uefi_protos_device_path_h_