OpenBSD supports System V shared memory. If XFree86 detects this support in your kernel, it will support the MIT-SHM extension.
To add support for system V shared memory to your kernel add the lines:
# System V-like IPC
options SYSVMSG
options SYSVSEM
options SYSVSHM
to your kernel config file. Then from /sys/arch/i386/config
, type:
# rm -f ../compile/<KERNEL-NAME>/*
# config <KERNEL-NAME>
# cd ../compile/<KERNEL-NAME>
# make depend
# make
Then install your new kernel and re-boot:
# cp /bsd /obsd
# cp bsd /
# reboot