cmake HAVE_SD_JOURNAL_OS_ROOT examples

netdata/netdata packaging/cmake/Modules/NetdataDetectSystemd.cmake :14 

check_c_source_compiles("
       #include <systemd/sd-journal.h>

       int main() {
           int x = SD_JOURNAL_OS_ROOT;
           return 0;
       }" HAVE_SD_JOURNAL_OS_ROOT)

netdata/netdata packaging/cmake/Modules/NetdataDetectSystemd.cmake :22 

check_symbol_exists(SD_JOURNAL_OS_ROOT "systemd/sd-journal.h" HAVE_SD_JOURNAL_OS_ROOT)