[MacPorts] #56664: enable diff-highlight in git, with variant

[MacPorts]

#56664: enable diff-highlight in git, with variant
----------------------+----------------------
  Reporter:  iEFdev   |      Owner:  ci42
      Type:  request  |     Status:  assigned
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:  2.5.2
Resolution:           |   Keywords:  haspatch
      Port:  git      |
----------------------+----------------------

Comment (by iEFdev):

 Replying to [comment:1 raimue]:
 > Variant names must not contain a minus as that would be ambiguous (it is
 used to negate variants). Apparently you have not tested this change, as
 the Portfile fails to parse.
 Sorry, my bad


 > Your notes do not describe what "functionality" they refer to.
 Yes, it sounded a bit vague... I changed it to:
 {{{
 --->  Staging git into destroot
 --->  Installing git
 @2.17.1_0+credential_osxkeychain+diff_highlight+doc+pcre+perl5_26
 --->  Activating git
 @2.17.1_0+credential_osxkeychain+diff_highlight+doc+pcre+perl5_26
 // … //
 --->  Some of the ports you installed have notes:
   git has the following notes:
     To add the use of "diff-highlight" to config, run:

         $ git config --global interactive.diffFilter diff-highlight
 }}}
 Better? Perhaps there's another terminlogy to use?


 > Now that you added a post-build to build the script, would it not also
 required to be copied in the destroot phase?
 No, the file/script stays in its contrib folder.

 // adding a new patch

-- 
Ticket URL: <https://trac.macports.org/ticket/56664#comment:2>
MacPorts <https://www.macports.org/>
Ports system for macOS