Display issue with -O2

[risc26z]

Hi,
I've found a minor bug that can be reproduced as follows:

Edit config.mk. Change to CONSOLE=sdl

Now edit Makefile. Append "-O2" to line beginning with "CFLAGS ="

make clean;make
sh msdos.sh
type 'dir' and hit enter

The issue is that a white or light grey bar appears on the right-hand side of the EMU86 window. It's harmless, but shouldn't be there. If you remove "-O2" from the CFLAGS line, the light-coloured bar does not appear. Trying -O3 or -Os gives compilation errors under gcc 14.3.1 due to a couple of possibly uninitialized variables.

I found this on an x86-64 system running Linux 6.17...