Set to not install kernel symbol files. This option is
recommended for those people who have small root partitions.
1. I think *.ko.symbols are no longer installed
2. With this build option defined the /boot/kernel directory is actually larger because the *.ko files include debug_info.
3. Without this option debug files are installed in /usr/lib/debug (even with option "WITHOUT_DEBUG_FILES" in src.conf)
To remove debug_info from kernel modules you have to
a) "makeoptions DEBUG=-g"
b) manually run "objcopy --strip-debug" on each *.ko