I've fixed the compile erroring out if the directories don't exist or you don't have permissions to perform the chmod, and have it explicitly changing the permissions on the current kernel source directory.
I understand there's still a problem if you're copying your compiled kernel to another machine (where you should have changed the permissions on those paths already, according to the kernel configuration help no one reads
) and there's no automatic resolution for that yet.
BTW, this chmodding only happens for people with GRKERNSEC_HIDESYM enabled, so it's specifically for people who neglect to read the kernel configuration help and thus reduce/negate the effectiveness of the option by having /proc/kallsyms removed but their kernel image still visible to everyone.
-Brad