Done in VirtualBuddy macOS guest running macOS Tahoe 26.6.2.
1. Install Apple’s command line tools

$ xcode-select --install

2. Install MacPorts from Installing MacPort

• The MacPorts Project is an open-source community initiative to design an easy-to-use system for compiling, installing, and upgrading either command-line, X11 or Aqua based open-source software on the Mac operating system.
• MacPorts installs to /opt/local by default.

3. Install geda-gschem

$ export PATH=/opt/local/bin:$PATH
$ sudo port install geda-gaf

If the build fails with error: static declaration of 'strchrnul' follows non-static declaration error, run equivalent of following command in build directory:

sudo perl -pi.bak -e 's/\bstrchrnul\b/geda_strchrnul/g' /opt/local/var/macports/build/geda-gaf-870cbe05/work/geda-gaf-1.10.2/gschem/src/x_controlfd.c

then rerun sudo port install geda-gaf
4. Install Xorg

sudo port install xorg-server

5. Restart macOS, then run gschem

$ /opt/local/bin/gschem

Done in VirtualBuddy macOS guest running macOS Tahoe 26.6.2. Since VirtualBuddy macOS guest does not support OpenGL, pcb has to be built without OpenGL support.
1. Configure pcb without OpenGL support

$ sudo port selfupdate
$ sudo port edit pcb

Add following line at the end of the file: configure.args-append –disable-gl
2. Install pcb from source

$ sudo port -s install pcb

2. Run gschem

$ /opt/local/bin/pcb