component/inkscape: add slapos python3 in PATH

this component needs both python2 and python3

component/inkscape/buildout.cfg

@@ -20,10 +20,11 @@ extends =
   ../patch/buildout.cfg
   ../perl/buildout.cfg
   ../pkgconfig/buildout.cfg
+  ../python3/buildout.cfg
   ../popt/buildout.cfg
   ../xorg/buildout.cfg
   ../zlib/buildout.cfg
-# Inkscape < 1.1 only supports python2 and old gcc
+# Inkscape < 1.1 only supports old gcc and needs python2 (and python3)
   ../python-2.7/buildout.cfg
   ../defaults.cfg
 
@@ -58,7 +59,7 @@ configure-options =
   -DWITH_LIBVISIO=OFF
   -DWITH_LIBWPG=OFF
 environment =
-  PATH=${cmake:location}/bin:${freetype:location}/bin:${gdk-pixbuf:location}/bin:${gettext:location}/bin:${glib:location}/bin:${intltool:location}/bin:${libxml2:location}/bin:${pango:location}/bin:${perl:location}/bin:${pkgconfig:location}/bin:${python2.7:location}/bin:%(PATH)s
+  PATH=${cmake:location}/bin:${freetype:location}/bin:${gdk-pixbuf:location}/bin:${gettext:location}/bin:${glib:location}/bin:${intltool:location}/bin:${libxml2:location}/bin:${pango:location}/bin:${perl:location}/bin:${pkgconfig:location}/bin:${python3:location}/bin:${python2.7:location}/bin:%(PATH)s
   PKG_CONFIG_PATH=${:pkg_config_depends}
   CMAKE_INCLUDE_PATH=${boost-lib:location}/include:${freetype:location}/include:${garbage-collector:location}/include:${libjpeg:location}/include:${lcms2:location}/include:${libpng:location}/include:${zlib:location}/include
   CMAKE_LIBRARY_PATH=${boost-lib:location}/lib:${freetype:location}/lib:${garbage-collector:location}/lib:${lcms2:location}/lib:${libjpeg:location}/lib:${libpng:location}/lib:${zlib:location}/lib