Build current FPC and Lazarus for Raspbian

Raspbian Buster (based on Debian 10 Buster) has FPC and Lazarus available in the repositories, but they suffer from the same "design decisions" that don't allow for a nice experience, namely the smooth IDE rebuilding capability based on source packages that is possible with FPC/Lazarus official .deb packages vs the crippled experience with the official Debian/Raspbian packages. One wishes there were official FPC/Lazarus packages for Raspbian as there are for Intel Debian/Ubuntu, which are also frequently updated; not being that the case (at least for now), this page shows the steps for building your own FPC, FPC-source and Lazarus packages for Raspbian.

Requirements:

• Raspberry Pi 4 4 GB
• Latest Raspbian fully up to date

Steps:

1. Install subversion: sudo apt install subversion
2. Get bootstrap FPC compiler
3. Extract compiler. This will create a fpc-3.0.2.arm-linux directory.
4. In this directory, as pi user, run ./install.sh
5. At the four prompts, answer Enter, n, n, n: this is, accept suggested directory /home/pi/fpc-3.0.2, no Textmode IDE, no documentation, no demos. Ignore tar warnings. Note the additional files written to /home/pi: .fpc.cfg, .config/fppkg.cfg, .fppkg/config/default. When the build is done, to delete this temporary bootstrap compiler these files and the /home/pi/fpc-3.0.2 install directory need to be deleted.
6. Temporarily add FPC install directory to PATH: export PATH=$PATH:$HOME/fpc-3.0.2/bin. If you reboot before completing the build you have to do this step again.
7. Test if all ok: fpc abcd. This invokes the just installed compiler trying to compile a non-existent file (abcd). A multiline message will be shown including the compiler version.