Qt6

Better document local the CMake module path and use it. Builds fine on my box. Check the MXE stuff with the Qt6 version of QCustomPlot.

CMakeStuff/toolchains/unix-toolchain-local.cmake

+message("UNIX non APPLE environment")
+message("Please run the configuration like this:")
+message("cmake -G \"Unix Makefiles\" -DCMAKE_BUILD_TYPE=Debug ../development")
+
+set(CMAKE_C_IMPLICIT_INCLUDE_DIRECTORIES /usr/include)
+set(CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES /usr/include)
+
+set(LINKER_FLAGS "-Wl,--no-as-needed")
+
+find_package(PwizLite REQUIRED) 
+
+find_package(ZLIB REQUIRED)
+
+find_package(Zstd REQUIRED)
+
+find_package(liblzf REQUIRED)
+
+find_package(Qt6 COMPONENTS Widgets Core Gui PrintSupport Svg REQUIRED)
+
+#find_package(QCustomPlotQt6 REQUIRED)
+
+set(QCustomPlotQt6_FOUND 1)
+SET(QCustomPlotQt6_INCLUDE_DIR "/home/langella/developpement/git/qcustomplot-qt6")
+SET(QCustomPlotQt6_LIBRARIES "/home/langella/developpement/git/qcustomplot-qt6/build-qt6/libQCustomPlotQt6.so" )
+
+	add_library(QCustomPlotQt6::QCustomPlotQt6 UNKNOWN IMPORTED)
+	set_target_properties(QCustomPlotQt6::QCustomPlotQt6 PROPERTIES
+		IMPORTED_LOCATION             "${QCustomPlotQt6_LIBRARIES}"
+		INTERFACE_INCLUDE_DIRECTORIES "${QCustomPlotQt6_INCLUDE_DIR}"
+		INTERFACE_COMPILE_DEFINITIONS QCUSTOMPLOTQT6_USE_LIBRARY)
+
+# Per instructions of the lib author:
+# https://www.qcustomplot.com/index.php/tutorials/settingup
+message(STATUS "Setting definition -DQCUSTOMPLOT_USE_LIBRARY.")
+
+add_definitions(-fPIC)
+
+message("unix-toolchain.cmake - LOCAL_CMAKE_MODULE_PATH: ${LOCAL_CMAKE_MODULE_PATH}")
+
+# Install the cmake module
+message("LOCAL_CMAKE_MODULE_PATH: ${LOCAL_CMAKE_MODULE_PATH}")
+install(FILES ${LOCAL_CMAKE_MODULE_PATH}/FindPappsoMSpp.cmake 
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/pappsomspp)
+
+# Configure the cmake config
+configure_file (${LOCAL_CMAKE_MODULE_PATH}/PappsoMSppConfig.cmake.in
+  ${CMAKE_BINARY_DIR}/PappsoMSppConfig.cmake)
+# Install the cmake config
+install(FILES ${CMAKE_BINARY_DIR}/PappsoMSppConfig.cmake 
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/pappsomspp)
+
+