[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/guid.h

@@ -0,0 +1,29 @@
+#pragma once
+#ifndef _uefi_guid_h_
+#define _uefi_guid_h_
+
+// This Source Code Form is part of the j6-uefi-headers project and is subject
+// to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was
+// not distributed with this file, You can obtain one at
+// http://mozilla.org/MPL/2.0/.
+
+#include <stdint.h>
+
+namespace uefi {
+
+struct guid
+{
+	uint32_t data1;
+	uint16_t data2;
+	uint16_t data3;
+	uint8_t data4[8];
+
+	inline bool operator==(const guid &other) const {
+		return reinterpret_cast<const uint64_t*>(this)[0] == reinterpret_cast<const uint64_t*>(&other)[0]
+			&& reinterpret_cast<const uint64_t*>(this)[1] == reinterpret_cast<const uint64_t*>(&other)[1];
+	}
+};
+
+} // namespace uefi
+
+#endif