wxgtk-3.0 opportunistically links to libsdl2 instead of libsdl

[barracuda156]

The port is supposed to use libsdl:

Full Name: wxgtk-3.0 @3.0.5.1_2+x11
Build Dependencies:   pkgconfig
Library Dependencies: libjpeg-turbo, tiff, libpng, zlib, libiconv, expat, cairo,
                      libsdl, libsdl_mixer, gtk3, mesa, libGLU
Runtime Dependencies: wxWidgets-common, wxWidgets_select

​https://ports.macports.org/port/wxgtk-3.0/details

Configure simply detects some SDL:

:info:configure checking for --with-sdl... yes
. . .
:info:configure checking for SDL... yes
. . .
:info:configure   Which GUI toolkit should wxWidgets use?                 GTK+ 3 with support for GTK+ printing libnotify
:info:configure   Should wxWidgets be compiled into single library?       no
:info:configure   Should wxWidgets be linked as a shared library?         yes
:info:configure   Should wxWidgets support Unicode?                       yes (using wchar_t)
:info:configure   What level of wxWidgets compatibility should be enabled?
:info:configure                                        wxWidgets 2.6      no
:info:configure                                        wxWidgets 2.8      yes
:info:configure   Which libraries should wxWidgets use?
:info:configure                                        STL                no
:info:configure                                        jpeg               sys
:info:configure                                        png                sys
:info:configure                                        regex              builtin
:info:configure                                        tiff               sys
:info:configure                                        zlib               sys
:info:configure                                        expat              sys
:info:configure                                        libmspack          no
:info:configure                                        sdl                yes
:debug:configure Executing portconfigure::configure_finish

However then the build does this:

:info:build /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_wxWidgets-3.0/wxgtk-3.0/work/wxWidgets-3.0.5.1/build/bk-deps /usr/bin/gcc-4.2 -c -o wxregex_regcomp.o -DNDEBUG -D__WXGTK__  -dynamic -fPIC -DPIC -D_FILE_OFFSET_BITS=64 -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_wxWidgets-3.0/wxgtk-3.0/work/wxWidgets-3.0.5.1/build/lib/wx/include/gtk3-unicode-3.0 -I../include -I/opt/local/include/gtk-3.0 -I/opt/local/include/at-spi2-atk/2.0 -I/opt/local/include/at-spi-2.0 -I/opt/local/include/dbus-1.0 -I/opt/local/lib/dbus-1.0/include -I/opt/local/include/gtk-3.0 -I/opt/local/include/gio-unix-2.0 -I/opt/local/include/cairo -I/opt/local/include/pango-1.0 -I/opt/local/include/harfbuzz -I/opt/local/include/pango-1.0 -I/opt/local/include/fribidi -I/opt/local/include/harfbuzz -I/opt/local/include/atk-1.0 -I/opt/local/include/cairo -I/opt/local/include/pixman-1 -I/opt/local/include/freetype2 -I/opt/local/include/gdk-pixbuf-2.0 -I/opt/local/include/libpng16 -I/opt/local/include/glib-2.0 -I/opt/local/lib/glib-2.0/include -D__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES=1 -I/opt/local/include -I/opt/local/include -Wall -Wundef -I/opt/local/include/gtk-3.0/unix-print -I/opt/local/include/gtk-3.0 -I/opt/local/include/at-spi2-atk/2.0 -I/opt/local/include/at-spi-2.0 -I/opt/local/include/dbus-1.0 -I/opt/local/lib/dbus-1.0/include -I/opt/local/include/gtk-3.0 -I/opt/local/include/gio-unix-2.0 -I/opt/local/include/cairo -I/opt/local/include/pango-1.0 -I/opt/local/include/harfbuzz -I/opt/local/include/pango-1.0 -I/opt/local/include/fribidi -I/opt/local/include/harfbuzz -I/opt/local/include/atk-1.0 -I/opt/local/include/cairo -I/opt/local/include/pixman-1 -I/opt/local/include/freetype2 -I/opt/local/include/gdk-pixbuf-2.0 -I/opt/local/include/libpng16 -I/opt/local/include/glib-2.0 -I/opt/local/lib/glib-2.0/include -D_THREAD_SAFE -I/opt/local/include/SDL2 -pipe -Os -arch i386 -fno-common -fvisibility=hidden ../src/regex/regcomp.c