Creates an LaunchAgent which correctly sets the SSH_AUTH_SOCK for all processes

create-ssh-agent-launchctl.sh

mkdir -p ~/Library/LaunchAgents
cat << EOF > ~/Library/LaunchAgents/com.dosburros.SSH_AUTH_SOCK.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>com.dosburros.SSH_AUTH_SOCK</string>
  <key>ProgramArguments</key>
  <array>
    <string>/bin/sh</string>
    <string>-c</string>
    <string>/bin/ln -sf $HOME/.ssh/agent.sock \$SSH_AUTH_SOCK</string>
  </array>
  <key>RunAtLoad</key>
  <true/>
</dict>
</plist>
EOF
launchctl load -w ~/Library/LaunchAgents/com.dosburros.SSH_AUTH_SOCK.plist