componnent/gtk-2: Add python2.7 as the dependency of pango

pango needs glib/glib-mkenums, and glib-mkenums needs python2.7:
-mkenums: /usr/bin/env: ‘python2.7’: No such file or directory

component/gtk-2/buildout.cfg

@@ -14,6 +14,7 @@ extends =
   ../libtool/buildout.cfg
   ../m4/buildout.cfg
   ../perl/buildout.cfg
+  ../python-2.7/buildout.cfg
   ../pkgconfig/buildout.cfg
   ../xorg/buildout.cfg
   ../icu/buildout.cfg
@@ -81,7 +82,7 @@ configure-options =
   --disable-static
   --disable-gtk-doc-html
 environment =
-  PATH=${glib:location}/bin:${freetype:location}/bin:${pkgconfig:location}/bin:${xz-utils:location}/bin:%(PATH)s
+  PATH=${python2.7:location}/bin:${glib:location}/bin:${freetype:location}/bin:${pkgconfig:location}/bin:${xz-utils:location}/bin:%(PATH)s
   PKG_CONFIG_PATH=${:pkg_config_depends}
   CPPFLAGS=-I${bzip2:location}/include -I${zlib:location}/include
   LDFLAGS=-L${bzip2:location}/lib -Wl,-rpath=${bzip2:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${harfbuzz:location}/lib -Wl,-rpath=${harfbuzz:location}/lib