Ticket 49305 - Need to wrap atomic calls
    
    Bug Description:  Some RHEL 7.5 platforms (ppc 32bit) still do not support
                      all the gcc builtin atomics.  This breaks the downstream
                      builds.
    
    Fix Description:  Use wrapper functions for the atomic's using #define's
                      to detect if builtin atomics are supported, otherwise
                      use the egneric nspr atomic functions.
    
    https://pagure.io/389-ds-base/issue/49305
    
    Reviewed by: tbordaz(Thanks!)