Merge branch 'dd/time-reentrancy'

Avoid gmtime() and localtime() and prefer their reentrant
counterparts.

* dd/time-reentrancy:
  mingw: use {gm,local}time_s as backend for {gm,local}time_r
  archive-zip.c: switch to reentrant localtime_r
  date.c: switch to reentrant {gm,local}time_r

diff --cc compat/mingw.c
Simple merge