bug#11058: Completion of error handling

[Markus Elfring]

Hello!

I have looked at a few source files for your current software. I have 
noticed that some checks for return codes are missing.

Would you like to add more error handling for return values from 
functions like the following?
- atexit ⇒ main

http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/date.c?id=3ba8b044267a5f7cfa8a7b0d7f19dab3f21431da#n320

- fputs ⇒ print_numbers

http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/seq.c?id=d3227eeb90c8308abd1e6bf08ee253b7a4e78d1d#n238

- printf ⇒ write_header

http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/head.c?id=d7878454cd02518959b0d6036db3a5b6ff00ca57#n162

Regards,
Markus