[MacPorts] #31392: sane-backends: clean up variant names

[MacPorts]

#31392: sane-backends: clean up variant names
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 Reporter:  ryandesign@…             |       Owner:  aguynamedryan+sane@…        
     Type:  enhancement              |      Status:  new                         
 Priority:  Normal                   |   Milestone:                              
Component:  ports                    |     Version:  2.0.3                       
 Keywords:                           |        Port:  sane-backends               
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 The sane-backends variants use prefixes, which is not how we usually name
 variants in MacPorts:

 {{{
 $ port variants sane-backends
 sane-backends has the variants:
    disable_localbackends: turn off compilation of all backends but net
      * conflicts with enable_pnmbackend with_gphoto2
    enable_pnmbackend: enable the pnm backend for testing frontends
 (possible security risk, see PROBLEMS file)
      * conflicts with disable_localbackends
    universal: Build for multiple architectures
    with_gphoto2: include the gphoto2 backend
      * conflicts with disable_localbackends
 }}}

  * "disable_localbackends" should invert its functionality and become
 "localbackends", default to on
  * "enable_pnmbackend" should become "pnmbackend" (or even just "pnm")
  * "with_gphoto2" should become "gphoto2"

 When the variants are renamed, stub variants with the old variant names
 should stay around for "awhile" (until "all" users have upgraded) to
 provide a migration path. For example:
 {{{
 variant disable_localbackends conflicts localbackends description {Legacy
 compatibility variant} {}
 if {[variant_isset disable_localbackends]} {
     default_variants -localbackends
 } else {
     default_variants +localbackends
 }
 variant enable_pnmbackend requires pnmbackend description {Legacy
 compatibility variant} {}
 variant with_gphoto2 requires gphoto2 description {Legacy compatibility
 variant} {}
 }}}
 And the revision should be increased when the variants are renamed.

-- 
Ticket URL: <https://trac.macports.org/ticket/31392>
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