lcdtest wasn’t working properly with German keyboard layouts. It was using keysyms from SDL key events, and those only indicate what the unshifted key legend is. The fix was to enable the optional SDL key event Unicode mapping, and switch on that rather than the keysym. However, some keys such as escape and the cursor arrows do not map to Unicode codepoints, and SDL returns a Unicode null for those. I added code to check for them and map them into values in the Unicode Private Use Area.
lcdtest 1.04 should work with any keyboard layout that the host system supports, assuming that SDL’s Unicode mapping is done properly.