docs: use GCC 10 toolchain for Linux builds

README.md

@@ -80,7 +80,7 @@ Windows 安装包会自动打包 `crossdesk_service.exe` 和 `crossdesk_session_
 
 依赖：
 - [xmake](https://xmake.io/#/guide/installation)
-- [cmake](https://cmake.org/download/) 3.21 及以上
+- [cmake](https://cmake.org/download/) 3.21 及以上（系统版本过低时由 xmake 自动安装）
 
 ### Linux
 
@@ -97,12 +97,11 @@ sudo apt-get install -y \
   libxtst-dev libxcb-randr0-dev libxcb-xtest0-dev libxcb-xinerama0-dev \
   libxcb-shape0-dev libxcb-xkb-dev libxcb-xfixes0-dev libxcb-shm0-dev \
   libasound2-dev libsndio-dev libpulse-dev
-
-# Ubuntu 20.04 自带的 CMake 3.16 不满足 Slint 1.17 的要求
-python3 -m pip install --user cmake==3.31.6
-export PATH="$HOME/.local/bin:$PATH"
 ```
 
+Ubuntu 20.04 自带的 CMake 3.16 不满足要求时，xmake 会自动下载并使用
+CMake 3.21 或更高版本，无需手动替换系统 CMake。
+
 Ubuntu 20.04 默认的 GCC 9 缺少 Slint C++ API 所需的部分 C++20 标准库，
 因此上述命令同时安装并在后续配置中指定 GCC 10。
 
@@ -128,17 +127,21 @@ git submodule update --init --recursive
 # 已安装发行版 PipeWire 0.3 开发包时可跳过此步骤。
 sudo ./docker/linux-build/install-pipewire-sdk.sh
 
-xmake f -m release --USE_CUDA=false --cc=gcc-10 --cxx=g++-10 -y
+xmake f -c -m release --USE_CUDA=false --toolchain=gcc-10 -y
 xmake b -vy crossdesk
 ```
 
+这里应使用 `--toolchain=gcc-10`，以确保 CrossDesk 及 xmake 在配置阶段构建的
+libyuv 等第三方包都使用 GCC 10。只指定 `--cc`/`--cxx` 时，依赖安装可能仍回退到
+系统默认的 `/bin/cc` 和 `/bin/c++`。`-c` 会清除旧配置，切换编译器时必须保留。
+
 amd64 构建结果位于 `build/linux/x86_64/release/crossdesk`，arm64 构建结果位于 `build/linux/arm64/release/crossdesk`。
 
 启用 Wayland 和 DRM 的配置示例：
 
 ```bash
-xmake f -m release --USE_WAYLAND=true --USE_DRM=true --USE_CUDA=false \
-  --cc=gcc-10 --cxx=g++-10 -y
+xmake f -c -m release --USE_WAYLAND=true --USE_DRM=true --USE_CUDA=false \
+  --toolchain=gcc-10 -y
 xmake b -vy crossdesk
 ```
 

README_EN.md

@@ -85,7 +85,7 @@ If the remote Windows service is not installed, not running, or temporarily unav
 
 Requirements:
 - [xmake](https://xmake.io/#/guide/installation)
-- [cmake](https://cmake.org/download/) 3.21 or later
+- [cmake](https://cmake.org/download/) 3.21 or later (installed automatically by xmake when the system version is too old)
 
 ### Linux
 
@@ -103,12 +103,12 @@ sudo apt-get install -y \
   libxtst-dev libxcb-randr0-dev libxcb-xtest0-dev libxcb-xinerama0-dev \
   libxcb-shape0-dev libxcb-xkb-dev libxcb-xfixes0-dev libxcb-shm0-dev \
   libasound2-dev libsndio-dev libpulse-dev
-
-# Ubuntu 20.04's CMake 3.16 is too old for Slint 1.17.
-python3 -m pip install --user cmake==3.31.6
-export PATH="$HOME/.local/bin:$PATH"
 ```
 
+When Ubuntu 20.04's bundled CMake 3.16 is too old, xmake automatically
+downloads and uses CMake 3.21 or later; replacing the system CMake manually is
+not required.
+
 Ubuntu 20.04's default GCC 9 lacks parts of the C++20 standard library needed
 by Slint's C++ API, so the commands above install GCC 10 and the configuration
 below selects it explicitly.
@@ -136,17 +136,23 @@ git submodule update --init --recursive
 # PipeWire 0.3 development packages are already installed.
 sudo ./docker/linux-build/install-pipewire-sdk.sh
 
-xmake f -m release --USE_CUDA=false --cc=gcc-10 --cxx=g++-10 -y
+xmake f -c -m release --USE_CUDA=false --toolchain=gcc-10 -y
 xmake b -vy crossdesk
 ```
 
+Use `--toolchain=gcc-10` so that both CrossDesk and third-party packages such
+as libyuv, which xmake builds during configuration, use GCC 10. Specifying only
+`--cc`/`--cxx` may still let dependency builds fall back to the system
+`/bin/cc` and `/bin/c++`. Keep `-c` when switching compilers to clear the old
+configuration.
+
 The amd64 binary is written to `build/linux/x86_64/release/crossdesk`; the arm64 binary is written to `build/linux/arm64/release/crossdesk`.
 
 Example configuration with Wayland and DRM capture enabled:
 
 ```bash
-xmake f -m release --USE_WAYLAND=true --USE_DRM=true --USE_CUDA=false \
-  --cc=gcc-10 --cxx=g++-10 -y
+xmake f -c -m release --USE_WAYLAND=true --USE_DRM=true --USE_CUDA=false \
+  --toolchain=gcc-10 -y
 xmake b -vy crossdesk
 ```
 

thirdparty/slint/xmake.lua

@@ -9,7 +9,7 @@ package("slint")
 
     add_configs("shared", {description = "Build the Slint runtime as a shared library", default = true, type = "boolean", readonly = true})
 
-    add_deps("cmake")
+    add_deps("cmake >=3.21 <4.0")
     add_deps("rust 1.92.0", {host = true, private = true, system = false})
 
     on_load(function(package)