component/freetype: Extend PATH to make xzcat available

This fixes 3c514224

component/freetype/buildout.cfg

@@ -7,6 +7,7 @@ extends =
   ../libpng/buildout.cfg
   ../pkgconfig/buildout.cfg
   ../zlib/buildout.cfg
+  ../xz-utils/buildout.cfg
 
 parts =
   freetype
@@ -24,7 +25,7 @@ configure-options =
   --without-brotli
   --without-librsvg
 environment =
-  PATH=${pkgconfig:location}/bin:%(PATH)s
+  PATH=${xz-utils:location}/bin:${pkgconfig:location}/bin:%(PATH)s
   PKG_CONFIG_PATH=${: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