75 lines
3.5 KiB
CMake
75 lines
3.5 KiB
CMake
# ----------------------------------------------------------------------------------
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# MANDATORY USER VARIABLE
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# ----------------------------------------------------------------------------------
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# IMPORTANT: This variable MUST be set when running CMake to specify where the
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# laptop's sysroot (the root directory of the mounted laptop filesystem) is located.
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#
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# Usage example: cmake -DCMAKE_TOOLCHAIN_FILE=laptop_x86_sysroot.cmake
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# -DTARGET_SYSROOT=/mnt/laptop_sysroot/ <path_to_source>
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#
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# If the variable is not defined, we fall back to a common system root path for safety.
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if(NOT DEFINED TARGET_SYSROOT)
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set(TARGET_SYSROOT "/usr/lib/x86_64-linux-gnu")
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message(STATUS "TARGET_SYSROOT not explicitly defined. Defaulting to ${TARGET_SYSROOT}")
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endif()
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# ----------------------------------------------------------------------------------
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# SYSROOT and COMPILER CONFIGURATION
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# ----------------------------------------------------------------------------------
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set(CMAKE_CROSSCOMPILING TRUE)
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# 1. Architecture and Platform Identification
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set(CMAKE_SYSTEM_NAME Linux)
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set(CMAKE_SYSTEM_PROCESSOR x86_64)
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set(TARGET_TRIPLE x86_64-linux-gnu) # Standard Debian/Ubuntu triple
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# 2. Set the CMAKE_SYSROOT using the user-defined variable
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set(CMAKE_SYSROOT ${TARGET_SYSROOT})
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message(STATUS "Using CMAKE_SYSROOT: ${CMAKE_SYSROOT}")
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# 3. Specify the Cross Compilers
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# These binaries must be installed on your RPi:
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# sudo apt install g++-x86-64-linux-gnu gcc-x86-64-linux-gnu
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set(CMAKE_C_COMPILER ${TARGET_TRIPLE}-gcc)
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set(CMAKE_CXX_COMPILER ${TARGET_TRIPLE}-g++)
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# ----------------------------------------------------------------------------------
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# PKG-CONFIG CONFIGURATION (CRUCIAL FOR CROSS-COMPILING)
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# ----------------------------------------------------------------------------------
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# 1. Define the search path for .pc files, relative to the sysroot.
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# This ensures we look in the target's standard pkgconfig locations.
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set(PKG_CONFIG_SEARCH_PATHS
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"${CMAKE_SYSROOT}/usr/lib/${TARGET_TRIPLE}/pkgconfig" # Primary location on Debian/Ubuntu
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"${CMAKE_SYSROOT}/usr/share/pkgconfig" # Secondary shared location
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"${CMAKE_SYSROOT}/usr/lib/pkgconfig" # Another common location
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)
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# Join the paths using the system's path separator (colon on Linux)
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string(REPLACE ";" ":" PKG_CONFIG_LIBDIR_STRING "${PKG_CONFIG_SEARCH_PATHS}")
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# Set the environment variable PKG_CONFIG_LIBDIR
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# This tells pkg-config exactly where to find the x86_64 .pc files.
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# 2. Set the sysroot directory for pkg-config
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# This tells pkg-config to prepend CMAKE_SYSROOT to any paths it finds in the .pc files.
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set(ENV{PKG_CONFIG_SYSROOT_DIR} ${CMAKE_SYSROOT})
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set(ENV{PKG_CONFIG_LIBDIR} ${PKG_CONFIG_LIBDIR_STRING})
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set(ENV{PKG_CONFIG_PATH} "")
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message(STATUS "PKG_CONFIG_SYSROOT_DIR set to: ${CMAKE_SYSROOT}")
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message(STATUS "PKG_CONFIG_LIBDIR set to: ${PKG_CONFIG_LIBDIR_STRING}")
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# ----------------------------------------------------------------------------------
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# CMAkE FIND BEHAVIOR
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# ----------------------------------------------------------------------------------
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# The CMAKE_FIND_ROOT_PATH tells CMake where to look for programs, libraries, etc.
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set(CMAKE_FIND_ROOT_PATH ${CMAKE_SYSROOT})
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# Restrict search to the sysroot, not in the RPi's native locations,
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# but allow programs (like pkg-config itself) to be found on the RPi.
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set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
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set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
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set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
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set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
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