Finally got around to putting the x64 version of Raspberry Pi OS on my Pi4b. Thought I'd just compile the tips and instructions from various other posts here, and my own hunting down of tips.

The following got me up and running painlessly more or less right from a clean install.

Code:
sudo apt install xdm x11-apps libx11-dev libvte9 subversion libtool make automake libpcap-dev libxext-dev
Should be all you need, and worked for me. But you can also do this which may include some for some reason missing packages (probably not necessary.)

Code:
sudo apt install subversion && sudo apt-get install build-essential && sudo apt-get install libpcap0.8-dev && sudo apt-get install zlib1g-dev && sudo apt-get install autoconf && sudo apt-get install automake && sudo apt-get install libtool && sudo apt-get install libx11-dev && sudo apt-get install libxext-dev && sudo apt-get install libpng-dev && sudo apt-get install libice-dev
Now we need QT5. We don't need everything listed per the instructions on the QT website though, so I remmed those out:

Code:
sudo apt-get install qtbase5-dev qtchooser
# sudo apt-get install qt5-qmake qtbase5-dev-tools
# sudo apt-get install qtcreator
# sudo apt-get install qtdeclarative5-dev
And that should do it. Get the code:

Code:
svn checkout http://svn.code.sf.net/p/seq/svn/showeq/tags/v6_3_5/ showeq-6.3.5
cd showeq-6.3.5
sudo make -f Makefile.dist build
And the important bit:

Code:
sudo ./configure --build=aarch64-unknown-linux-gnu --with-qt-libraries=/usr/lib/aarch64-linux-gnu
And hopefully that'll do it:

Code:
sudo make
sudo make install
Make your life easier and grab permission on the maps and filters directories.

Code:
sudo chown -R username:username /usr/local/share/showeq
sudo chown -R username:username /usr/local/share/showeq/maps
sudo chown -R username:username /usr/local/share/showeq/filters
Copy your client's version of eqstr_us.txt and spells_us.txt over to /usr/local/share/showeq. Put your maps (brewalls or goods work fine) into the appropriate dirs.

Code:
sudo showeq
Might need to specify the IP of your EQ Client machine. Zone in and hopefully you have skittles!

Play nice!