gnuplot: question about wxWidgets(-devel) & Universal variants

[Mojca Miklavec]

Hello,

I would like to use gnuplot with wxt terminal (wxWidgets). The current
Portfile uses

    variant wxwidgets description "Enable wxWidgets front-end" {
        depends_lib-append      port:wxWidgets
        configure.args-delete   --disable-wxwidgets
        configure.args-append   --with-wx-config=${prefix}/bin/wx-config
    }
    if {[variant_isset wxwidgets]} {
        # wxWidgets is not universal and is 32-bit only
        universal_variant       no
        supported_archs         i386 ppc
    }

however wxWidgets 2.8 only support Carbon (= only ppc and i386). I
have tried to modify the gnuplot's Portfile to use wxWidgets 2.9. The
following code works for me (Lion x86_64):

    variant wxwidgets description "Enable wxWidgets front-end" {
        depends_lib-append      port:wxWidgets-devel
        configure.args-delete   --disable-wxwidgets
        configure.args-append   --with-wx-config=${prefix}/bin/wx-config
    }
    if {[variant_isset wxwidgets]} {
        if {${configure.compiler} == "clang"} {
            configure.compiler llvm-gcc-4.2
        }
    }

but since many other ports depend on wxWidgets (conflicting with
wxWidgets-devel), it might be undesirable to put the code above to
gnuplot's Portfile. Also, for anyone using ppc or i386 the version 2.8
of wxWidgets might be perfectly OK.

How exactly should the code be written to enable compiling 64-bit
version of gnuplot with wxt terminal, without interfering with other
ports and without breaking functionality for 32-bit architectures?
Once/if that question is answered, I have a Portfile for the new
gnuplot 4.6 ready to be committed.

Thank you,
    Mojca