[MacPorts] #65630: GraphicsMagick: add debug variant

[MacPorts]

#65630: GraphicsMagick: add debug variant
-----------------------------+----------------------
  Reporter:  mascguy         |      Owner:  mascguy
      Type:  enhancement     |     Status:  assigned
  Priority:  Normal          |  Milestone:
 Component:  ports           |    Version:  2.7.2
Resolution:                  |   Keywords:  debug
      Port:  GraphicsMagick  |
-----------------------------+----------------------

Comment (by parafin):

 Replying to [comment:7 mascguy]:
 > Relative to the signal handlers, it looks like apps can now explicitly
 disable those. Functionality was added to the `GraphicsMagick` API in
 version 1.3.35, released 2020-02-23:
 >
 > > InitializeMagickEx(): New function which may be used in place of
 InitializeMagick() to initialize GraphicsMagick. This initialization
 function returns an error status value, may update a passed ExceptionInfo
 structure with error information, and provides an options parameter which
 supports simple bit-flags to tailor initialization. The signal handler
 registrations are skipped if the MAGICK_OPT_NO_SIGNAL_HANDER flag is set
 in the options.
 >
 > @parafin, is that something you folks want to try, for `darktable`?

 PR submitted to darktable to be tested. IMHO it's still backwards, signal
 handler installation should be opt-in, not opt-out. But I do understand
 that it's more a question for upstream, not macports.

-- 
Ticket URL: <https://trac.macports.org/ticket/65630#comment:11>
MacPorts <https://www.macports.org/>
Ports system for macOS