# pkg_check_variable() - a function to retrieve pkg-config variables in CMake
#
# source: http://bloerg.net/2015/03/06/pkg-config-variables-in-cmake.html

find_package(PkgConfig REQUIRED)

function(pkg_check_variable _pkg _name)
    string(TOUPPER ${_pkg} _pkg_upper)
    string(TOUPPER ${_name} _name_upper)
    string(REPLACE "-" "_" _pkg_upper ${_pkg_upper})
    string(REPLACE "-" "_" _name_upper ${_name_upper})
    set(_output_name "${_pkg_upper}_${_name_upper}")

    execute_process(COMMAND ${PKG_CONFIG_EXECUTABLE} --variable=${_name} ${_pkg}
                    OUTPUT_VARIABLE _pkg_result
                    OUTPUT_STRIP_TRAILING_WHITESPACE)

    set("${_output_name}" "${_pkg_result}" CACHE STRING "pkg-config variable ${_name} of ${_pkg}")
endfunction()