I just built and replaced graphviz on NetBSD 10 amd64 without incident.
On NetBSD 11 amd64, I previously hadn't had it, and 'make
package-install' led to newly-installed packages:
-rw-r--r-- 1 root wheel 548 Mar 19 20:11 glib2-tools-2.86.4
-rw-r--r-- 1 root wheel 878 Mar 19 20:11 gettext-lib-0.22.5
-rw-r--r-- 1 root wheel 19560 Mar 19 20:11 gettext-tools-0.22.5nb1
-rw-r--r-- 1 root wheel 17403 Mar 19 20:11 bison-3.8.2nb1
-rw-r--r-- 1 root wheel 299 Mar 19 20:11 osabi-NetBSD-11.0_RC2
-rw-r--r-- 1 root wheel 108135 Mar 19 20:11 x11-links-1.36
-rw-r--r-- 1 root wheel 5573 Mar 19 20:11 urw-fonts-2.0nb1
-rw-r--r-- 1 root wheel 52629 Mar 19 20:12 netpbm-11.02.09nb8
-rw-r--r-- 1 root wheel 1753 Mar 19 20:12 gts-0.7.6nb7
-rw-r--r-- 1 root wheel 92891 Mar 19 20:12 meson-1.10.1
-rw-r--r-- 1 root wheel 19460 Mar 19 20:12 gobject-introspection-1.86.0
-rw-r--r-- 1 root wheel 6766 Mar 19 20:12 libXft-2.3.9
-rw-r--r-- 1 root wheel 6571 Mar 19 20:13 pango-1.57.0nb2
-rw-r--r-- 1 root wheel 24152 Mar 19 20:22 graphviz-14.1.3
are you talking about -current, and if so from what day? "modern" is
hard to understnad.