build fixes + gentoo cross docs

Signed-off-by: crueter <crueter@eden-emu.dev>

CMakeModules/GentooCross.cmake

@@ -0,0 +1,18 @@
+# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+set(CROSS_TARGET "powerpc64le" CACHE STRING "Cross-compilation target (aarch64, powerpc64le, riscv64, etc)")
+
+set(CMAKE_SYSROOT /usr/${CROSS_TARGET}-unknown-linux-gnu)
+
+set(CMAKE_C_COMPILER ${CROSS_TARGET}-unknown-linux-gnu-gcc)
+set(CMAKE_CXX_COMPILER ${CROSS_TARGET}-unknown-linux-gnu-g++)
+
+# search programs in the host environment
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+
+# search headers and libraries in the target environment
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+
+set(CMAKE_FIND_ROOT_PATH /usr/${CROSS_TARGET}-unknown-linux-gnu)

docs/CrossCompile.md

@@ -2,7 +2,122 @@
 
 General guide for cross compiling.
 
-## Debian ARM64
+## Gentoo
+
+Gentoo's cross-compilation setup is relatively easy, provided you're already familiar with portage.
+
+### Crossdev
+
+First, emerge crossdev via `sudo emerge -a sys-devel/crossdev`.
+
+Now, set up the environment depending on the target architecture; e.g.
+
+```sh
+sudo crossdev powerpc64le
+sudo crossdev aarch64
+```
+
+### QEMU
+
+Installing a qemu user setup is recommended for testing. To do so, you will need the relevant USE flags:
+
+```sh
+app-emulation/qemu static-user qemu_user_targets_ppc64le qemu_user_targets_aarch64
+```
+
+Note that to use cross-emerged libraries, you will need to tell qemu where the sysroot is. You can do this with an alias:
+
+```sh
+alias qemu-ppc64le="qemu-ppc64le -L /usr/powerpc64le-unknown-linux-gnu"
+alias qemu-aarch64="qemu-aarch64 -L /usr/aarch64-unknown-linux-gnu"
+```
+
+### Dependencies
+
+Some packages have broken USE flags on other architectures; you'll also need to set up python targets. In `/usr/<target>-unknown-linux-gnu/etc/portage/package.use`:
+
+```sh
+>=net-misc/curl-8.16.0-r1 ssl
+
+*/* PYTHON_TARGETS: python3_13 PYTHON_SINGLE_TARGET: python3_13
+*/* pam
+
+sys-apps/util-linux pam su
+app-shells/bash -readline
+>=dev-libs/libpcre2-10.47 unicode
+>=x11-libs/libxkbcommon-1.12.3 X
+>=sys-libs/zlib-1.3.1-r1 minizip
+>=app-alternatives/gpg-1-r3 ssl
+>=app-crypt/gnupg-2.5.13-r2 ssl
+
+dev-libs/* -introspection
+media-libs/harfbuzz -introspection
+dev-libs/quazip -qt5 qt6
+```
+
+Dependencies should be about the same [as normal Gentoo](./Deps.md), but removing gamemode and renderdoc is recommended. Keep in mind that when emerging, you want to use `emerge-<target>-unknown-linux-gnu`, e.g. `emerge-powerpc64le-unknown-linux-gnu`.
+
+Enable GURU in the cross environment (as root):
+
+```sh
+mkdir -p /usr/powerpc64le-unknown-linux-gnu/etc/portage/repos.conf
+cat << EOF > /usr/powerpc64le-unknown-linux-gnu/etc/portage/repos.conf/guru.conf
+[guru]
+location = /var/db/repos/guru
+auto-sync = no
+priority = 1
+EOF
+```
+
+Now emerge your dependencies:
+
+```sh
+sudo emerge-powerpc64le-unknown-linux-gnu -aU app-arch/lz4 app-arch/zstd app-arch/unzip \
+    dev-libs/libfmt dev-libs/libusb dev-libs/mcl dev-libs/sirit dev-libs/oaknut \
+    dev-libs/unordered_dense dev-libs/boost dev-libs/openssl dev-libs/discord-rpc \
+    dev-util/spirv-tools dev-util/spirv-headers dev-util/vulkan-headers \
+    dev-util/vulkan-utility-libraries dev-util/glslang \
+    media-libs/libva media-libs/opus media-video/ffmpeg \
+    media-libs/VulkanMemoryAllocator media-libs/libsdl2 media-libs/cubeb \
+    net-libs/enet net-libs/mbedtls \
+    sys-libs/zlib \
+    dev-cpp/nlohmann_json dev-cpp/simpleini dev-cpp/cpp-httplib dev-cpp/cpp-jwt dev-cpp/catch \
+    net-wireless/wireless-tools \
+    dev-qt/qtbase:6 dev-libs/quazip \
+    virtual/pkgconfig
+```
+
+### Building
+
+A toolchain is provided in `CMakeModules/GentooCross.cmake`. To use it:
+
+```sh
+cmake -S . -B build/ppc64 -DCMAKE_TOOLCHAIN_FILE=CMakeModules/GentooCross.cmake -G Ninja -DCROSS_TARGET=powerpc64le -DENABLE_OPENGL=OFF
+```
+
+Now build as normal:
+
+```sh
+cmake --build build/ppc64 -j$(nproc)
+```
+
+### Alternatively
+
+Only emerge the absolute necessities:
+
+```sh
+sudo emerge-powerpc64le-unknown-linux-gnu -aU media-video/ffmpeg media-libs/libsdl2 dev-qt/qtbase:6
+```
+
+Then set `YUZU_USE_CPM=ON`:
+
+```sh
+cmake -S . -B build/ppc64 -DCMAKE_TOOLCHAIN_FILE=CMakeModules/GentooCross.cmake -G Ninja -DCROSS_TARGET=powerpc64le -DENABLE_OPENGL=OFF -DYUZU_USE_CPM=ON
+```
+
+## ARM64
+
+### Debian ARM64
 
 A painless guide for cross compilation (or to test NCE) from a x86_64 system without polluting your main.
 
@@ -20,6 +135,7 @@ Now you got a PowerPC sysroot - quickly decompress it somewhere, say `/home/user
 There is a script to automatically do all of this under `./tools/setup-cross-sysroot.sh`
 
 Specify:
+
 - `YUZU_USE_CPM`: Set this to `ON` so packages can be found and built if your sysroot doesn't have them.
 - `YUZU_USE_EXTERNAL_FFMPEG`: Set this to `ON` as well.
 

externals/powah/CMakeLists.txt

@@ -3,6 +3,7 @@
 
 add_library(powah INTERFACE)
 target_include_directories(powah INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
+target_compile_options(powah INTERFACE -Wno-unused-parameter)
 
 add_executable(powah_tests tests.cpp)
 create_target_directory_groups(powah_tests)

externals/powah/powah_emit.hpp

@@ -5,10 +5,10 @@
 #include <cstdint>
 #include <cstddef>
 #include <cassert>
-#include <ranges>
-#include <bit>
+#include <vector>
 #include <utility>
 #include <sys/mman.h>
+#include <cstdlib>
 
 //#ifndef __cpp_lib_unreachable
 namespace std {

src/dynarmic/src/dynarmic/backend/exception_handler_posix.cpp

@@ -7,6 +7,7 @@
  */
 
 #include <cstring>
+#include <algorithm>
 #include <functional>
 #include <memory>
 #include <mutex>

src/dynarmic/src/dynarmic/backend/ppc64/reg_alloc.cpp

@@ -5,6 +5,7 @@
 #include <algorithm>
 #include <array>
 #include <ranges>
+#include <variant>
 
 #include "dynarmic/backend/ppc64/reg_alloc.h"
 #include "dynarmic/backend/ppc64/abi.h"