graphviz binary on OSX 15.2 x86_64

[Bill Hill]

Hi, I've just upgraded from Ventura to Sequoia (Now on MacOS 15.2, Xcode 16.2) and I've got several ports to go that
depend on graphviz, which isn't playing.

If I try "sudo port install -b graphviz" I get a 404 for https://packages.macports.org/graphviz/
but it looks like there's been a build: https://build.macports.org/builders/ports-15_x86_64-builder/builds/22685

Also, if I try a local build, it fails to configure: "configure: error: *** A compiler with support for C++17 language features is required."
Any ideas?
Thanks.
Bill