[Boost-build] Is it possible to set a features default value with an indirect conditional target ?

Subject: [Boost-build] Is it possible to set a features default value with an indirect conditional target ?
From: Kuhl, Brian (brian.kuhl_at_[hidden])
Date: 2016-06-18 03:05:31

My failed attempt follows.

rule default_abi ( properties * )
{
    local tmp = sysv ;

    if [ os.platform ] = "ARM" { tmp = aapcs ; }
    else if [ os.platform ] = "MIPS" { tmp = o32 ; }
    else if ( <target-os>vxworks in $(properties) )  { tmp = sysv ; }
    else if [ os.name ] = "NT" { tmp = ms ; }
    return $(tmp) ;
}

rule set_default_abi ( )
{
    local abi =   <conditional>@default_abi  ;
    return $(abi)  ;
}

feature.feature abi
   : aapcs
     eabi
     ms
     n32
     n64
     o32
     o64
     sysv
     x32
   : propagated
   ;
feature.set-default abi : [ set_default_abi ] ;