Debian 12交叉编译时CMake无法找到sysroot中的xkbcommon-x11

在Debian 12（WSL）主机上进行AArch64交叉编译时，CMake无法定位xkbcommon-x11库，但相同的sysroot和CMake版本（3.28.3）在Ubuntu 24.04（WSL）上可正常工作。以下是测试用的相关文件、输出及解决方案：

测试文件 #

CMakeLists.txt #

cmake_minimum_required(VERSION 3.18)
project(Test)

find_package(PkgConfig QUIET)

# pkg_check_modules(XKB_COMMON_X11 IMPORTED_TARGET "xkbcommon-x11>=0.4.1")
pkg_check_modules(XKB_COMMON_X11 IMPORTED_TARGET "xkbcommon-x11")

if (NOT TARGET PkgConfig::XKB_COMMON_X11)
    set(XKB_COMMON_X11_FOUND 0)
endif()

message("XKB_COMMON_X11_FOUND: ${XKB_COMMON_X11_FOUND}")
message("XKB_COMMON_X11_VERSION: ${XKB_COMMON_X11_VERSION}")

toolchain.cmake #

cmake_minimum_required(VERSION 3.18)
include_guard(GLOBAL)

set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR aarch64)

IF(NOT DEFINED ENV{sroot})
  message(FATAL_ERROR "Please set the environment variable sroot to the path of the sysroot")
ENDIF()
IF (NOT EXISTS $ENV{sroot}/usr/include)
  message(FATAL_ERROR "It seems that the sysroot image is not mounted. Please mount it first.")
ENDIF()
set(TARGET_SYSROOT $ENV{sroot})
set(CMAKE_SYSROOT ${TARGET_SYSROOT})

set(ENV{PKG_CONFIG_PATH} $PKG_CONFIG_PATH:/usr/lib/aarch64-linux-gnu/pkgconfig)
set(ENV{PKG_CONFIG_LIBDIR} /usr/lib/pkgconfig:/usr/share/pkgconfig/:${TARGET_SYSROOT}/usr/lib/aarch64-linux-gnu/pkgconfig:${TARGET_SYSROOT}/usr/lib/pkgconfig)
set(ENV{PKG_CONFIG_SYSROOT_DIR} ${CMAKE_SYSROOT})

# if you use other version of gcc and g++ than gcc/g++ 9, you must change the following variables
set(CMAKE_C_COMPILER /usr/bin/aarch64-linux-gnu-gcc-12)
set(CMAKE_CXX_COMPILER /usr/bin/aarch64-linux-gnu-g++-12)

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -isystem=/usr/include -isystem=/usr/include/aarch64-linux-gnu")
set(CMAKE_CXX_FLAGS "${CMAKE_C_FLAGS}")

set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
set(CMAKE_BUILD_RPATH ${TARGET_SYSROOT})

运行命令 #

cmake . --toolchain toolchain.cmake

输出对比 #

Ubuntu 24.04 输出 #

-- The C compiler identification is GNU 12.3.0
-- The CXX compiler identification is GNU 12.3.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/aarch64-linux-gnu-gcc-12 - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/aarch64-linux-gnu-g++-12 - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Checking for module 'xkbcommon-x11'
--   Found xkbcommon-x11, version 1.5.0
XKB_COMMON_X11_FOUND: 1
XKB_COMMON_X11_VERSION: 1.5.0

-- Configuring done (7.7s)
-- Generating done (0.0s)

Debian 12 输出 #

-- The C compiler identification is GNU 12.2.0
-- The CXX compiler identification is GNU 12.2.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/aarch64-linux-gnu-gcc-12 - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/aarch64-linux-gnu-g++-12 - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
XKB_COMMON_X11_FOUND: 0
XKB_COMMON_X11_VERSION: 
-- Configuring done
-- Generating done

更新信息 #

Ubuntu上验证库来源，确认是sysroot中的文件：

PkgConfig::XKB_COMMON_X11 INTERFACE_LINK_LIBRARIES = /home/a/buildimg/root/usr/lib/aarch64-linux-gnu/libxkbcommon-x11.so;/home/a/buildimg/root/usr/lib/aarch64-linux-gnu/libxkbcommon.so

原因分析 #

1. Debian缺少交叉编译依赖包：Ubuntu默认预装了xkbcommon-x11的交叉编译pkg-config文件，而Debian需要手动安装对应架构的开发包。
2. pkg-config环境变量配置问题：Debian对PKG_CONFIG_PATH/PKG_CONFIG_LIBDIR的解析逻辑与Ubuntu存在差异，导致无法正确定位sysroot中的.pc文件。

解决步骤 #

步骤1：安装Debian交叉编译开发包 #

在Debian 12 WSL中执行以下命令，安装AArch64架构的xkbcommon-x11开发包：

sudo apt install libxkbcommon-x11-dev:aarch64

步骤2：调整toolchain.cmake的pkg-config环境变量 #

修改环境变量配置，确保pkg-config优先从sysroot查找，避免主机路径干扰：

# 清空原有路径，仅保留sysroot相关的pkg-config目录
set(ENV{PKG_CONFIG_PATH} "${TARGET_SYSROOT}/usr/lib/aarch64-linux-gnu/pkgconfig:${TARGET_SYSROOT}/usr/lib/pkgconfig")
# 明确指定pkg-config的库目录
set(ENV{PKG_CONFIG_LIBDIR} "${TARGET_SYSROOT}/usr/lib/aarch64-linux-gnu/pkgconfig:${TARGET_SYSROOT}/usr/lib/pkgconfig")
# 确保sysroot目录正确设置
set(ENV{PKG_CONFIG_SYSROOT_DIR} ${CMAKE_SYSROOT})

步骤3：手动验证pkg-config可用性（可选） #

在Debian WSL中直接运行pkg-config命令，测试是否能定位到库：

PKG_CONFIG_SYSROOT_DIR=$sroot PKG_CONFIG_LIBDIR=${sroot}/usr/lib/aarch64-linux-gnu/pkgconfig pkg-config --modversion xkbcommon-x11

如果输出版本号，说明配置生效，重新运行CMake即可。

步骤4：直接指定pc文件路径（ fallback方案） #

若上述方法无效，可在CMakeLists.txt中直接指定.pc文件路径：

pkg_check_modules(XKB_COMMON_X11 IMPORTED_TARGET "${TARGET_SYSROOT}/usr/lib/aarch64-linux-gnu/pkgconfig/xkbcommon-x11.pc")

内容的提问来源于stack exchange，提问作者maestro