contrib/wix/defines.wxi

configitems: extract the logic to build a registrar on any configtable

Having the logic available independently from the mapping used is a necessary
step toward extensions support.

<Include>

  <?if $(var.Platform) = "x64" ?>
    <?define IsX64 = yes ?>
  <?else?>
    <?define IsX64 = no ?>
  <?endif?>

</Include>