Reduce awk(1), grep(1), seq(1), and stat(1) usage.
    
    subr/build_init.subr:buildp_init_files(): replace timestamp w/ running total log filename suffix.
    subr/build_init.subr:buildp_init_prereqs(): ensure sed(1) supports -i option.
    subr/rtl_complex.subr:rtl_{get_cpu_count,is_newer}(): initial implementation.
    subr/rtl_string.subr:rtl_match(): initial implementation.