[MacPorts] #33259: cmake portgroup: out of source build option, possibly by default

[MacPorts]

#33259: cmake portgroup: out of source build option, possibly by default
---------------------------+--------------------------------
  Reporter:  ryandesign@…  |      Owner:  macports-tickets@…
      Type:  enhancement   |     Status:  new
  Priority:  Normal        |  Milestone:
 Component:  ports         |    Version:
Resolution:                |   Keywords:
      Port:                |
---------------------------+--------------------------------

Comment (by mojca@…):

 There's another aspect that I forgot about. Thanks for pointing it out.
 Once we do the necessary changes globally or in the PortGroup we could
 simply change the individual CMake-based ports to opt-in one-by-one. Then
 a single commit would just set the variable default to ON in the CMake
 PortGroup (and next commit would just remove all those opt-ins in CMake-
 based ports). Then we wouldn't have any pressure or fears of unexpected
 failures.

 What's the best way to introduce a new global variable (if we can agree on
 that and its name)? Does one need to upgrade MacPorts for the change to
 take effect? (If we would need an upgrade, it might be better to first
 introduce in the CMake PortGroup nevertheless and then move it to a global
 place once a new release comes to the horizon.)

-- 
Ticket URL: <https://trac.macports.org/ticket/33259#comment:15>
MacPorts <https://www.macports.org/>
Ports system for OS X