[cmake, docs] Reorganize CMakeModules directory and add GentooCross toolchain (#4088)

Lightly inspired by my earlier toolchain and writeup from the PowerPC
PR.

Closes #3793

Signed-off-by: crueter <crueter@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4088
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

CMakeModules/WindowsCopyFiles.cmake

@@ -1,39 +0,0 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
-# SPDX-License-Identifier: GPL-3.0-or-later
-
-# SPDX-FileCopyrightText: 2018 yuzu Emulator Project
-# SPDX-License-Identifier: GPL-2.0-or-later
-
-# This file provides the function windows_copy_files.
-# This is only valid on Windows.
-
-# Include guard
-if(__windows_copy_files)
-	return()
-endif()
-set(__windows_copy_files YES)
-
-# Any number of files to copy from SOURCE_DIR to DEST_DIR can be specified after DEST_DIR.
-# This copying happens post-build.
-if (CMAKE_HOST_SYSTEM_NAME STREQUAL "Windows")
-    function(windows_copy_files TARGET SOURCE_DIR DEST_DIR)
-        # windows commandline expects the / to be \ so switch them
-        string(REPLACE "/" "\\\\" SOURCE_DIR ${SOURCE_DIR})
-        string(REPLACE "/" "\\\\" DEST_DIR ${DEST_DIR})
-
-        # /NJH /NJS /NDL /NFL /NC /NS /NP - Silence any output
-        # cmake adds an extra check for command success which doesn't work too well with robocopy
-        # so trick it into thinking the command was successful with the || cmd /c "exit /b 0"
-        add_custom_command(TARGET ${TARGET} POST_BUILD
-            COMMAND ${CMAKE_COMMAND} -E make_directory ${DEST_DIR}
-            COMMAND robocopy ${SOURCE_DIR} ${DEST_DIR} ${ARGN} /NJH /NJS /NDL /NFL /NC /NS /NP || cmd /c "exit /b 0"
-        )
-    endfunction()
-else()
-    function(windows_copy_files TARGET SOURCE_DIR DEST_DIR)
-        add_custom_command(TARGET ${TARGET} POST_BUILD
-            COMMAND ${CMAKE_COMMAND} -E make_directory ${DEST_DIR}
-            COMMAND cp -ra ${SOURCE_DIR}/. ${DEST_DIR}
-        )
-    endfunction()
-endif()

CMakeModules/aqt_config.ini

@@ -1,30 +0,0 @@
-# SPDX-FileCopyrightText: 2024 kleidis
-
-[aqt]
-concurrency: 2
-
-[mirrors]
-trusted_mirrors:
-    https://download.qt.io
-blacklist:
-    https://qt.mirror.constant.com
-    https://mirrors.ocf.berkeley.edu
-    https://mirrors.ustc.edu.cn
-    https://mirrors.tuna.tsinghua.edu.cn
-    https://mirrors.geekpie.club
-    https://mirrors-wan.geekpie.club
-    https://mirrors.sjtug.sjtu.edu.cn
-fallbacks:
-    https://qtproject.mirror.liquidtelecom.com/
-    https://mirrors.aliyun.com/qt/
-    https://ftp.jaist.ac.jp/pub/qtproject/
-    https://ftp.yz.yamagata-u.ac.jp/pub/qtproject/
-    https://qt-mirror.dannhauer.de/
-    https://ftp.fau.de/qtproject/
-    https://mirror.netcologne.de/qtproject/
-    https://mirrors.dotsrc.org/qtproject/
-    https://www.nic.funet.fi/pub/mirrors/download.qt-project.org/
-    https://master.qt.io/
-    https://mirrors.ukfast.co.uk/sites/qt.io/
-    https://ftp2.nluug.nl/languages/qt/
-    https://ftp1.nluug.nl/languages/qt/

CMakeModules/find/FindDiscordRPC.cmake

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 # SPDX-FileCopyrightText: 2022 Alexandre Bouvier <contact@amb.tf>

CMakeModules/find/FindFFmpeg.cmake

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 # SPDX-FileCopyrightText: 2019 Citra Emulator Project

CMakeModules/find/FindOpus.cmake

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 # SPDX-FileCopyrightText: 2022 yuzu Emulator Project

CMakeModules/find/FindRenderDoc.cmake

@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # SPDX-FileCopyrightText: 2023 Alexandre Bouvier <contact@amb.tf>
 #
 # SPDX-License-Identifier: GPL-3.0-or-later

CMakeModules/find/FindSimpleIni.cmake

@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # SPDX-FileCopyrightText: 2023 Alexandre Bouvier <contact@amb.tf>
 #
 # SPDX-License-Identifier: GPL-3.0-or-later

CMakeModules/find/Findenet.cmake

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 # SPDX-FileCopyrightText: 2022 Alexandre Bouvier <contact@amb.tf>

CMakeModules/find/Findgamemode.cmake

@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # SPDX-FileCopyrightText: 2023 yuzu Emulator Project
 # SPDX-License-Identifier: GPL-2.0-or-later
 

CMakeModules/find/Findhttplib.cmake

@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # SPDX-FileCopyrightText: 2022 Andrea Pappacoda <andrea@pappacoda.it>
 #
 # SPDX-License-Identifier: GPL-2.0-or-later

CMakeModules/find/Findlibiw.cmake

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 find_package(PkgConfig QUIET)

CMakeModules/find/Findlibusb.cmake

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 # SPDX-FileCopyrightText: 2022 Alexandre Bouvier <contact@amb.tf>

CMakeModules/find/Findlz4.cmake

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 # SPDX-FileCopyrightText: 2022 yuzu Emulator Project

CMakeModules/find/Findstb.cmake

@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # SPDX-FileCopyrightText: 2023 Alexandre Bouvier <contact@amb.tf>
 #
 # SPDX-License-Identifier: GPL-3.0-or-later

CMakeModules/find/Findzstd.cmake

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 # SPDX-FileCopyrightText: 2022 yuzu Emulator Project

CMakeModules/toolchains/GentooCross.cmake

@@ -0,0 +1,39 @@
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+set(CROSS_TARGET "" CACHE STRING "Cross-compilation target (aarch64, etc)")
+set(CROSS_PLATFORM "unknown-linux-gnu" CACHE STRING "Cross-compilation platform (e.g. unknown-linux-gnu)")
+set(CROSS_COMPILER "gcc" CACHE STRING "Cross compiler type (gcc or clang)")
+
+if (NOT CROSS_TARGET)
+    message(FATAL_ERROR "GentooCross used without a valid CROSS_TARGET")
+endif()
+
+set(prefix ${CROSS_TARGET}-${CROSS_PLATFORM})
+
+set(CMAKE_SYSROOT /usr/${prefix})
+
+if (CROSS_COMPILER STREQUAL "gcc")
+    set(CMAKE_C_COMPILER ${prefix}-gcc)
+    set(CMAKE_CXX_COMPILER ${prefix}-g++)
+elseif (CROSS_COMPILER STREQUAL "clang")
+    set(CMAKE_C_COMPILER ${prefix}-clang)
+    set(CMAKE_CXX_COMPILER ${prefix}-clang++)
+else()
+    message(FATAL_ERROR "Unsupported cross compiler type ${CROSS_COMPILER}")
+endif()
+
+# search programs in the host environment
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+
+# search headers and libraries in the target environment
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+
+set(CMAKE_FIND_ROOT_PATH ${CMAKE_SYSROOT})
+
+# sanity checks
+if (NOT IS_DIRECTORY ${CMAKE_SYSROOT})
+    message(FATAL_ERROR "Invalid sysroot ${CMAKE_SYSROOT}."
+        "Double-check your CROSS_TARGET and CROSS_PLATFORM.")
+endif()