Implementing firmware version

What operating system are you using?

Under Windows, you would set the path via the control panel. Under Linux you can use scripts that get executed at login.

In either case, you can set the variable before you start Quartus if you use a command-line shell, eg., start a NIOS II IDE shell, and type

export PATH=$PATH:"C:/program files/TortoiseSVN/bin"
quartus

and then Quartus will start, with the PATH extended to include the path to SVN.

Of course, you now have non-portable HDL build system. Personally, I'd look into a solution where when you check into/out of SVN, a file is created with the SVN version info. You can then use Quartus to parse that file, and there is no need to worry about SVN being in the path for Quartus.

Cheers,

Dave