lib/, src/: Always pass NULL to time(2)

lib/, src/: Always pass NULL to time(2)

See time(2):

BUGS
     Error returns from this system  call  are  indistinguishable  from
     successful  reports  that  the  time  is  a few seconds before the
     Epoch, so the C library wrapper function never sets errno as a re‐
     sult of this call.

     The tloc argument is obsolescent and should always be NULL in  new
     code.  When tloc is NULL, the call cannot fail.

Fixes: 45c6603cc86c ("[svn-upgrade] Integrating new upstream version, shadow (19990709)")
Signed-off-by: Alejandro Colomar <alx@kernel.org>