graphviz must not be used in fedora-20, otherise it never terminates

libxml-cxx.spec.in

@@ -5,7 +5,10 @@ Release: @BUILD_NUMBER@%{?dist}
 License: LGPL
 Group: Development/Libraries/C++
 Source0: %{name}-%{version}.tar.gz
-BuildRequires: gnupg, subversion, automake, autoconf, doxygen, graphviz
+BuildRequires: gnupg, subversion, automake, autoconf, doxygen
+%if 0%{?fedora} != 20
+BuildRequires: graphviz
+%endif
 BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root
 %if 0%{?fedora} || 0%{?rhel} || 0%{?rhl} || 0%{?centos} || 0%{?centos_ver} || 0%{?centos_version}
 BuildRequires: pkgconfig, redhat-lsb, cppunit-devel