saving subprocess output in local copy, tee, and exit codes

[René J. V. Bertin]

A bit to my surprise this works with the sort of complex cmake commandlines I 
get in my KF5 ports:

{{{
proc cmake.save_configure_cmd {{save_log_too ""}} {
    if {${save_log_too} ne ""} {
        pre-configure {
            configure.pre_args-prepend "-cf '${configure.cmd} "
            configure.post_args-append "|& tee ${workpath}/.macports.
${subport}.configure.log'"
            configure.cmd "/bin/csh"
            ui_debug "configure command set to `${configure.cmd} 
${configure.pre_args} ${configure.args} ${configure.post_args}`"
        }
    }
# etc
}}}

R