Instead, I chose to seek out the general features provided by KDE for this type of thing. As it turns out, there are three special directories that KDE uses to handle starting and stopping of programs and the handling of the environment when logging in.
Enabling ssh-agent and populating the environment
ssh-agent must sbe running, and the appropriate environment variables defined in order to use it. KDE provides the directory .kde/env for just such a purpose. In there, executable scripts are run and let you define new environments. I put the following into ssh-agent.sh and made that file executable.
#!/bin/sh eval `/usr/bin/ssh-agent`
Adding your private keys
You use ssh-add(1) in order to add your keys into the ssh-agent program. To do this, I have another script similiar to the ssh-agent.sh called ssh-add.sh (also executable), that is placed in the .kde/Autostart directory.
#!/bin/sh SSH_ASKPASS=/usr/bin/x11-ssh-askpass /usr/bin/ssh-add
You will note that the program x11-ssh-askpass is not installed by default in Slackware. I used the SlackBuild provided by SlackBuilds.org for this purpose. I modified the script a bit so that it suited me, and then went ahead with the normal build and install process.
Stopping ssh-agent on logout
At first, I thought I was done once the above steps were completed. However, I soon learned that the ssh agent will stay running even after I logout. To fix this, I use another script in the .kde/shutdown directory.
#!/bin/sh /usr/bin/ssh-agent -k
which will kill the appropriate daemon on exit.