--- Mk/bsd.default-versions.mk.orig
+++ Mk/bsd.default-versions.mk
@@ -21,7 +21,7 @@
 
 .for lang in APACHE BDB COROSYNC EMACS FIREBIRD FORTRAN FPC GCC GHOSTSCRIPT \
 	IMAGEMAGICK JAVA JULIA LAZARUS LIBRSVG2 LINUX LLVM LUA MYSQL PERL5 \
-	PGSQL PHP PYTHON PYTHON2 PYTHON3 RUBY RUST SAMBA SSL TCLTK VARNISH
+	PGSQL PHP PYTHON PYTHON2 PYTHON3 RUBY RUST SAMBA SSL TCLTK VARNISH VTK
 .if defined(${lang}_DEFAULT)
 ERROR+=	"The variable ${lang}_DEFAULT is set and it should only be defined through DEFAULT_VERSIONS+=${lang:tl}=${${lang}_DEFAULT} in /etc/make.conf"
 .endif
@@ -153,5 +153,8 @@
 
 # Possible values: 4, 6
 VARNISH_DEFAULT?=	4
+
+# Possible values: 6, 8, 9
+VTK_DEFAULT?=		9
 
 .endif