chore: make yuzu REUSE compliant

[REUSE] is a specification that aims at making file copyright
information consistent, so that it can be both human and machine
readable. It basically requires that all files have a header containing
copyright and licensing information. When this isn't possible, like
when dealing with binary assets, generated files or embedded third-party
dependencies, it is permitted to insert copyright information in the
`.reuse/dep5` file.

Oh, and it also requires that all the licenses used in the project are
present in the `LICENSES` folder, that's why the diff is so huge.
This can be done automatically with `reuse download --all`.

The `reuse` tool also contains a handy subcommand that analyzes the
project and tells whether or not the project is (still) compliant,
`reuse lint`.

Following REUSE has a few advantages over the current approach:

- Copyright information is easy to access for users / downstream
- Files like `dist/license.md` do not need to exist anymore, as
  `.reuse/dep5` is used instead
- `reuse lint` makes it easy to ensure that copyright information of
  files like binary assets / images is always accurate and up to date

To add copyright information of files that didn't have it I looked up
who committed what and when, for each file. As yuzu contributors do not
have to sign a CLA or similar I couldn't assume that copyright ownership
was of the "yuzu Emulator Project", so I used the name and/or email of
the commit author instead.

[REUSE]: https://reuse.software

Follow-up to 01cf05bc75b1e47beb08937439f3ed9339e7b254

24 files changed, 49 insertions, 69 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index c1cc62a45..a614b176b 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: 2018 yuzu Emulator Project
+# SPDX-License-Identifier: GPL-2.0-or-later
+
 add_library(core STATIC
     announce_multiplayer_session.cpp
     announce_multiplayer_session.h
diff --git a/src/core/arm/arm_interface.h b/src/core/arm/arm_interface.h
index c092db9ff..73f259525 100644
--- a/src/core/arm/arm_interface.h
+++ b/src/core/arm/arm_interface.h
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/arm/dynarmic/arm_dynarmic_cp15.cpp b/src/core/arm/dynarmic/arm_dynarmic_cp15.cpp
index 6aae79c48..e9123c13d 100644
--- a/src/core/arm/dynarmic/arm_dynarmic_cp15.cpp
+++ b/src/core/arm/dynarmic/arm_dynarmic_cp15.cpp
@@ -1,6 +1,5 @@
-// Copyright 2017 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2017 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <fmt/format.h>
 #include "common/logging/log.h"
diff --git a/src/core/arm/dynarmic/arm_dynarmic_cp15.h b/src/core/arm/dynarmic/arm_dynarmic_cp15.h
index f271b2070..5b2a51636 100644
--- a/src/core/arm/dynarmic/arm_dynarmic_cp15.h
+++ b/src/core/arm/dynarmic/arm_dynarmic_cp15.h
@@ -1,6 +1,5 @@
-// Copyright 2017 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2017 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/core.cpp b/src/core/core.cpp
index 95791a07f..ea32a4a8d 100644
--- a/src/core/core.cpp
+++ b/src/core/core.cpp
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <array>
 #include <atomic>
diff --git a/src/core/core.h b/src/core/core.h
index 13122dd61..0ce3b1d60 100644
--- a/src/core/core.h
+++ b/src/core/core.h
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/file_sys/errors.h b/src/core/file_sys/errors.h
index ff15b3e23..7cee0c7df 100644
--- a/src/core/file_sys/errors.h
+++ b/src/core/file_sys/errors.h
@@ -1,6 +1,5 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2016 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/frontend/emu_window.cpp b/src/core/frontend/emu_window.cpp
index 57c6ffc43..1be2dccb0 100644
--- a/src/core/frontend/emu_window.cpp
+++ b/src/core/frontend/emu_window.cpp
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <mutex>
 #include "core/frontend/emu_window.h"
diff --git a/src/core/frontend/emu_window.h b/src/core/frontend/emu_window.h
index b3bffecb2..ac1906d5e 100644
--- a/src/core/frontend/emu_window.h
+++ b/src/core/frontend/emu_window.h
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/ipc.h b/src/core/hle/ipc.h
index 602e12606..416da15ec 100644
--- a/src/core/hle/ipc.h
+++ b/src/core/hle/ipc.h
@@ -1,6 +1,5 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2016 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/ipc_helpers.h b/src/core/hle/ipc_helpers.h
index 004bb2005..d631c0357 100644
--- a/src/core/hle/ipc_helpers.h
+++ b/src/core/hle/ipc_helpers.h
@@ -1,6 +1,5 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2016 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/kernel/k_client_port.cpp b/src/core/hle/kernel/k_client_port.cpp
index d63e77d15..3cb22ff4d 100644
--- a/src/core/hle/kernel/k_client_port.cpp
+++ b/src/core/hle/kernel/k_client_port.cpp
@@ -1,6 +1,5 @@
-// Copyright 2021 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2021 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "common/scope_exit.h"
 #include "core/hle/kernel/hle_ipc.h"
diff --git a/src/core/hle/kernel/k_client_port.h b/src/core/hle/kernel/k_client_port.h
index ef8583efc..e17eff28f 100644
--- a/src/core/hle/kernel/k_client_port.h
+++ b/src/core/hle/kernel/k_client_port.h
@@ -1,6 +1,5 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2016 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/kernel/k_process.cpp b/src/core/hle/kernel/k_process.cpp
index b662788b3..d3e99665f 100644
--- a/src/core/hle/kernel/k_process.cpp
+++ b/src/core/hle/kernel/k_process.cpp
@@ -1,6 +1,5 @@
-// Copyright 2015 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2015 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <algorithm>
 #include <bitset>
diff --git a/src/core/hle/kernel/k_process.h b/src/core/hle/kernel/k_process.h
index 5e3e22ad8..d56d73bab 100644
--- a/src/core/hle/kernel/k_process.h
+++ b/src/core/hle/kernel/k_process.h
@@ -1,6 +1,5 @@
-// Copyright 2015 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2015 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/kernel/k_shared_memory.cpp b/src/core/hle/kernel/k_shared_memory.cpp
index b77735736..8ff1545b6 100644
--- a/src/core/hle/kernel/k_shared_memory.cpp
+++ b/src/core/hle/kernel/k_shared_memory.cpp
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "common/assert.h"
 #include "core/core.h"
diff --git a/src/core/hle/kernel/k_shared_memory.h b/src/core/hle/kernel/k_shared_memory.h
index 2c1db0e70..34cb98456 100644
--- a/src/core/hle/kernel/k_shared_memory.h
+++ b/src/core/hle/kernel/k_shared_memory.h
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/hle/result.h b/src/core/hle/result.h
index aa9e5b89d..4de44cd06 100644
--- a/src/core/hle/result.h
+++ b/src/core/hle/result.h
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/memory.cpp b/src/core/memory.cpp
index 635449fce..1b44280b5 100644
--- a/src/core/memory.cpp
+++ b/src/core/memory.cpp
@@ -1,6 +1,5 @@
-// Copyright 2015 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2015 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <algorithm>
 #include <cstring>
diff --git a/src/core/memory.h b/src/core/memory.h
index 780c45385..2a21fbcfd 100644
--- a/src/core/memory.h
+++ b/src/core/memory.h
@@ -1,6 +1,5 @@
-// Copyright 2014 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2014 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/perf_stats.cpp b/src/core/perf_stats.cpp
index 6ef459b7a..f09c176f8 100644
--- a/src/core/perf_stats.cpp
+++ b/src/core/perf_stats.cpp
@@ -1,6 +1,5 @@
-// Copyright 2017 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2017 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <algorithm>
 #include <chrono>
diff --git a/src/core/perf_stats.h b/src/core/perf_stats.h
index 816202588..dd6becc02 100644
--- a/src/core/perf_stats.h
+++ b/src/core/perf_stats.h
@@ -1,6 +1,5 @@
-// Copyright 2017 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2017 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
diff --git a/src/core/telemetry_session.cpp b/src/core/telemetry_session.cpp
index 654db0b52..abcf6eb11 100644
--- a/src/core/telemetry_session.cpp
+++ b/src/core/telemetry_session.cpp
@@ -1,6 +1,5 @@
-// Copyright 2017 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2017 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <array>
 
diff --git a/src/core/telemetry_session.h b/src/core/telemetry_session.h
index 6f3d45bea..887dc98f3 100644
--- a/src/core/telemetry_session.h
+++ b/src/core/telemetry_session.h
@@ -1,6 +1,5 @@
-// Copyright 2017 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
+// SPDX-FileCopyrightText: 2017 Citra Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once