Implement a new check that tests for Y2038 problems
glibc on 32 bit architectures defaults to 32 bit types to hold timestamps. These cannot hold dates later than Jan 19 2038. With the right cpp defines a 64bit type can be used which is future-proof for quite some time.
I think this is a pressing matter, so I'd like to drop "Experimental: yes", but I sticked to it because that's what the LFS check does, too.
Edited by Uwe Kleine-König