if(APPLE)

    if(${CMAKE_VERSION} VERSION_GREATER "2.8.10.2" AND

       ${CMAKE_VERSION} VERSION_LESS "2.8.12.1")

        message(FATAL_ERROR "This version of CMake is known *not* to work, please update or use a lower version")

    endif()

    set(CMAKE_FIND_FRAMEWORK "FIRST")

    #what system are we building for

    set(minimum_macosx_version $ENV{MACOSX_DEPLOYMENT_TARGET})

    #detect on which system we are: if sw_vers cannot be found for any reason (re)use minimum_macosx_version

    find_program(sw_vers sw_vers)

    if(sw_vers)

        execute_process(COMMAND ${sw_vers} "-productVersion"

                        OUTPUT_VARIABLE current_macosx_version

                        OUTPUT_STRIP_TRAILING_WHITESPACE)

        string(REGEX REPLACE "([0-9]+.[0-9]+).[0-9]+" "\\1" current_macosx_version ${current_macosx_version})

    else()

        if(NOT minimum_macosx_version)

            message(FATAL_ERROR "sw_vers not found! Need explicit MACOSX_DEPLOYMENT_TARGET variable set")

        else()

            message("*** sw_vers not found! Fallback to MACOSX_DEPLOYMENT_TARGET variable ***")

            set(current_macosx_version ${minimum_macosx_version})

        endif()

    endif()

    #if nothing is set, we deploy only for the current system

    if(NOT minimum_macosx_version)

        set(minimum_macosx_version ${current_macosx_version})

    endif()

    #10.3 systems don't have enough processing power anyway

    #10.4 does not have @rpath support (which SDL uses)

    if(minimum_macosx_version VERSION_LESS "10.5")

        message(FATAL_ERROR "Hedgewars is not supported on your version of Mac OS X")

    endif()

    if(NOT CMAKE_OSX_ARCHITECTURES)

        if(current_macosx_version VERSION_LESS "10.6")

            #SDL is only 32 bit on older OS version

            if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "powerpc*")

                set(CMAKE_OSX_ARCHITECTURES "ppc7400")

            else()

                set(CMAKE_OSX_ARCHITECTURES "i386")

            endif()

        endif()

    endif()

    #parse this system variable and adjust only the powerpc syntax to be compatible with -P

    if(CMAKE_OSX_ARCHITECTURES)

        string(REGEX MATCH "[pP][pP][cC]+" powerpc_build "${CMAKE_OSX_ARCHITECTURES}")

        string(REGEX MATCH "[iI]386+" i386_build "${CMAKE_OSX_ARCHITECTURES}")

        string(REGEX MATCH "[xX]86_64+" x86_64_build "${CMAKE_OSX_ARCHITECTURES}")

        if(x86_64_build)

            add_flag_prepend(CMAKE_Pascal_FLAGS -Px86_64)

        elseif(i386_build)

            add_flag_prepend(CMAKE_Pascal_FLAGS -Pi386)

        elseif(powerpc_build)

            add_flag_prepend(CMAKE_Pascal_FLAGS -Ppowerpc)

        else()

            message(FATAL_ERROR "Unknown architecture present in CMAKE_OSX_ARCHITECTURES (${CMAKE_OSX_ARCHITECTURES})")

        endif()

        list(LENGTH CMAKE_OSX_ARCHITECTURES num_of_archs)

        if(num_of_archs GREATER 1)

            message("*** Only one architecture in CMAKE_OSX_ARCHITECTURES is supported, picking the first one ***")

        endif()

    elseif(CMAKE_SIZEOF_VOID_P MATCHES "8")

        #if that variable is not set check if we are on x86_64 and if so force it, else use default

        add_flag_prepend(CMAKE_Pascal_FLAGS -Px86_64)

    endif()

    #CMAKE_OSX_SYSROOT is set at the system version we are supposed to build on

    #we need to provide the correct one when host and target differ

    if(NOT CMAKE_OSX_SYSROOT AND

       NOT ${minimum_macosx_version} VERSION_EQUAL ${current_macosx_version})

        find_program(xcrun xcrun)

        if(xcrun)

            execute_process(COMMAND ${xcrun} "--show-sdk-path"

                            OUTPUT_VARIABLE current_sdk_path

                            OUTPUT_STRIP_TRAILING_WHITESPACE)

            string(REPLACE "${current_macosx_version}"

                           "${minimum_macosx_version}"

                           CMAKE_OSX_SYSROOT

                           "${current_sdk_path}")

        else()

            message("*** xcrun not found! Build will work on ${current_macosx_version} only ***")

        endif()

    endif()

    if(CMAKE_OSX_SYSROOT)

        add_flag_append(CMAKE_Pascal_FLAGS "-XR${CMAKE_OSX_SYSROOT}")

        add_flag_append(CMAKE_Pascal_FLAGS "-k-macosx_version_min -k${minimum_macosx_version}")

        add_flag_append(CMAKE_Pascal_FLAGS "-k-L${LIBRARY_OUTPUT_PATH} -Fl${LIBRARY_OUTPUT_PATH}")

    endif()

    #add user framework directory

    add_flag_append(CMAKE_Pascal_FLAGS "-Ff~/Library/Frameworks")

    #workaround older cmake versions

    if(${CMAKE_VERSION} VERSION_LESS "2.8.12")

        add_flag_append(CMAKE_C_LINK_FLAGS "-Wl,-rpath -Wl,${CMAKE_INSTALL_RPATH}")

        add_flag_append(CMAKE_CXX_LINK_FLAGS "-Wl,-rpath -Wl,${CMAKE_INSTALL_RPATH}")

        add_flag_append(CMAKE_Pascal_LINK_FLAGS "-k-rpath -k${CMAKE_INSTALL_RPATH}")

    endif()

endif(APPLE)

if(MINGW)

    #this flags prevents a few dll hell problems

    add_flag_append(CMAKE_C_FLAGS "-static-libgcc")

    add_flag_append(CMAKE_CXX_FLAGS "-static-libgcc")

endif(MINGW)

if(WIN32)

    if(NOT ${BUILD_SHARED_LIB})

        message(FATAL_ERROR "Static linking is not supported on Windows")

    endif()

endif(WIN32)

if(UNIX)

    add_flag_append(CMAKE_C_FLAGS "-fPIC")

    add_flag_append(CMAKE_CXX_FLAGS "-fPIC")

endif(UNIX)