component/graphviz: version ↑ 2.40.1

Also enable expat

note about the URL: it's not downloading from the official
https://graphviz.gitlab.io/pub/graphviz/stable/SOURCES/graphviz.tar.gz
because that one has not version number in URL. I took a random mirror
on the internet after verifying signature was same.

component/graphviz/buildout.cfg

@@ -9,12 +9,13 @@ extends =
   ../gtk-2/buildout.cfg
   ../pkgconfig/buildout.cfg
   ../zlib/buildout.cfg
+  ../libexpat/buildout.cfg
 
 [graphviz]
 recipe = slapos.recipe.cmmi
 shared = true
-url = http://www.graphviz.org/pub/graphviz/stable/SOURCES/graphviz-2.38.0.tar.gz
-md5sum = 5b6a829b2ac94efcd5fa3c223ed6d3ae
+url = https://ftp.osuosl.org/pub/blfs/conglomeration/graphviz/graphviz-2.40.1.tar.gz
+md5sum = 4ea6fd64603536406166600bcc296fc8
 pkg_config_depends = ${pango:location}/lib/pkgconfig:${pango:pkg_config_depends}
 configure-options =
   --with-included-ltdl
@@ -22,6 +23,7 @@ configure-options =
   --with-zlibdir=${zlib:location}/lib
   --with-freetype2
   --with-fontconfig
+  --with-expat
   --disable-swig
   --disable-sharp
   --disable-go
@@ -37,7 +39,6 @@ configure-options =
   --disable-ruby
   --disable-tcl
   --without-x
-  --without-expat
   --without-devil
   --without-webp
   --without-poppler
@@ -59,5 +60,5 @@ configure-options =
 environment =
   PATH=${pkgconfig:location}/bin:%(PATH)s
   PKG_CONFIG_PATH=${:pkg_config_depends}
-  CPPFLAGS=-I${zlib:location}/include
-  LDFLAGS=-L${bzip2:location}/lib -Wl,-rpath=${bzip2:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib
+  CPPFLAGS=-I${zlib:location}/include -I${libexpat:location}/include
+  LDFLAGS=-L${bzip2:location}/lib -Wl,-rpath=${bzip2:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${libexpat:location}/lib -Wl,-rpath=${libexpat:location}/lib