#2468 make pkg for macOS to produce graphviz.pkg
This request defines a Makefile to build a macOS installer package. Its changes
- updates macosx/graphviz.xcodeproj to build for Apple Silicon and macOS 13.5 Ventura and later.
- adds macosx/build/Distribution.xml to define the contents of the graphviz installer package.
- adds macosx/build/Makefile to build the contents of a 'make dist' distribution and package it.
- specifies in .gitignore that macosx/build/Makefile should be tracked and graphviz.pkg should not be.
The resulting package file, when executed
- installs the binaries and libraries of graphviz into /usr/local/graphviz. This helps to isolate the install from other packages installed in /usr/local.
- defines /etc/paths.d/graphviz to add graphviz/bin to PATH.
- installs Graphviz.app in the /Applications folder.