compiling from sources

You need 2 packages installed on your system to compile ssh-pull-id:
1. Subversion - this will provide svn command to fetch the source code
2. fpc - this is the FreePascal compiler that you will use to compile the code
3. build-essential - this may or may not be already on your system. It contains most basic toolchain that compilers use

So the entire procedure to get the source and compile the binary is this:

$ sudo apt-get -q -y install subversion build-essential fpc
#fetch the code:
$ svn checkout https://svn.code.sf.net/p/ssh-pull-id/code/ ssh-pull-id-code
#and compile:
$ cd ssh-pull-id-code
$ fpc ssh-pull-id.pas
#and optionally (but recommended) strip the executable:
$ strip ssh-pull-id

The last part about stripping the executable, in case you are not sure what it is about: when you compile the program it has a built-in debug information that debugger uses. It add extra size to the executable. And as a user you are not going to need this anyways, so when you strip your executable you take that extra debugging information out of you executable and it results in a much smaller size.

The above procedure is specific to Ubuntu, should work the same way od other Debian based distributions.
It works on Ubuntu desktop (x86_64), and ARM, so also for example on Raspberry Pi running Ubuntu Mate Desktop.
On Ubuntu Touch it works as well, but:
1. The rootfs on UT is read-only so you would need to remount it as writable before proceeding
2. The free space on the rootfs of UT is quite small and installing this all can cause you run out of it.
So in the download section a pre-compiled binary version for ARM is available for download, so you can just download it and run. That version will work on all ARM Linux distros.