cmake influence example

cmake_minimum_required(VERSION 3.6)

set(CMAKE_C_STANDARD 11)
set(CMAKE_VERBOSE_MAKEFILE on)
set(CMAKE_C_VISIBILITY_PRESET hidden)

# thanks to http://stackoverflow.com/questions/7172670
function(join OUTPUT GLUE)
    set(_TMP_RESULT "")
    set(_GLUE "") # effective glue is empty at the beginning
    foreach(arg ${ARGN})
        set(_TMP_RESULT "${_TMP_RESULT}${_GLUE}${arg}")
        set(_GLUE "${GLUE}")
    endforeach()
    set(${OUTPUT} "${_TMP_RESULT}" PARENT_SCOPE)
endfunction(join)

function(append_env NAME VAL)
    set(TMP $ENV{${NAME}})
    set(ENV{${NAME}} "${TMP} ${VAL}")
endfunction(append_env)

function(set_empty OUTPUT VAL)
    if ((NOT DEFINED ${OUTPUT}) OR "${OUTPUT}" STREQUAL "")
        set(${OUTPUT} "${VAL}" PARENT_SCOPE)
    endif()
endfunction(set_empty)

function(influence_pkg_spec TGT PREFIX)

    if (TARGET ${TGT})
        join(TMP " " ${${PREFIX}_CFLAGS})
        target_compile_options(${TGT} PUBLIC ${TMP})
        join(TMP " " ${${PREFIX}_CFLAGS_OTHER})
        target_compile_options(${TGT} PUBLIC ${TMP})
        join(TMP " " ${${PREFIX}_LDFLAGS})
        set_property(TARGET ${TGT} APPEND_STRING PROPERTY LINK_FLAGS " ${TMP} ")
        join(TMP " " ${${PREFIX}_LDFLAGS_OTHER})
        set_property(TARGET ${TGT} APPEND_STRING PROPERTY LINK_FLAGS " ${TMP} ")
    endif()

endfunction(influence_pkg_spec)

function(influence_pkg PREFIX)
    if (${PREFIX}_FOUND)
        influence_pkg_spec(test1 ${PREFIX})
    endif()
endfunction(influence_pkg)

set(ENV{CMAKE_APPBUNDLE_PATH} "/opt/soft/cjose")
set_property(GLOBAL PROPERTY INSTALL_RPATH_USE_LINK_PATH TRUE)
set_property(GLOBAL PROPERTY BUILD_WITH_INSTALL_RPATH TRUE)
set(LIB_SOURCE ${LIB_SOURCE} linux_port/config.h linux_port/port.c)

add_executable(test1 test.c)


include(FindPkgConfig)

pkg_check_modules(JSONC REQUIRED json-c)
pkg_check_modules(CJOSE REQUIRED cjose)

influence_pkg("JSONC")
influence_pkg("CJOSE")