[MacPorts] #50199: gnuplot: opportunistically uses gtk2 when building with wxwidgets enabled

[MacPorts]

#50199: gnuplot: opportunistically uses gtk2 when building with wxwidgets enabled
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  Reporter:  devans@…  |      Owner:  mojca@…
      Type:  defect    |     Status:  new
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:
Resolution:            |   Keywords:
      Port:  gnuplot   |
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Comment (by mojca@…):

 Here's Ethan's response (I'm not sure why it didn't get automatically
 added to Trac):
 > The autoconfigure script assume `pkg-config` will correctly
 > provide the include and lib directories for whatever version
 > of gtk is appropriate.   If not, then according to `./configure --help`
 > you can set
 {{{
    GTK_CFLAGS  C compiler flags for GTK, overriding pkg-config
    GTK_LIBS    linker flags for GTK, overriding pkg-config
 }}}

 ----

 Ethan, `pkg-config` works ok and finds the right flags for GTK 2. The
 problem is that users here don't want to link against GTK at all because
 wxWigets use the Cocoa backend on OS X rather than GTK. As a consequence
 gnuplot gets linked against GTK 2 without using any GTK functionality at
 all.

 But even in some extreme cases when OS X users would demand the use of
 wxGTK, the current check is still wrong because users might have wxWidgets
 built against GTK 3 as in the example I pointed out above. I can test it,
 but I believe this would then break badly. The following would be true:
 {{{
 #if defined(__WXGTK__)&&defined(HAVE_GTK)
 # define USE_GTK
 #endif
 }}}
 and then gnuplot would try to link against both GTK 2 and GTK 3 at the
 same time. `WX_LIBS` has the following value:
 {{{
 -framework IOKit -framework CoreServices -framework System -framework
 ApplicationServices -lwx_gtk3u_xrc-3.0 -lwx_gtk3u_html-3.0
 -lwx_gtk3u_qa-3.0 -lwx_gtk3u_adv-3.0 -lwx_gtk3u_core-3.0
 -lwx_baseu_xml-3.0 -lwx_baseu_net-3.0 -lwx_baseu-3.0
 }}}
 and GTK 2 libs would be added on top of that.

-- 
Ticket URL: <https://trac.macports.org/ticket/50199#comment:4>
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