I managed to get this working on my DSTT.
In main.cpp, around line 280, you try and get the location the app is running from from argv[0], which appears to be null on DSTT.
I commented out:
strncpy(bootdir, argv[0], len);
and added after it:
bootdir[0] = '/';
bootdir[1] = '\0';
Compiled, and runs fine for me now. The .ini has to stay in the root of the drive.
Attached is my modified version, and the modified source is there too. Hope I am not stepping on anyone's toes by sharing it.
savegame_manager_0.2.3_dstt.zip