Revert "gnu: coreutils: Disable 64-bit time_t on 32-bit systems."

This reverts commit 4eebb73295.

The ‘--disable-year2038’ flag appears to be unnecessary (tested on
i686-linux).  More importantly, it’s potentially harmful as it could
prevent rebuilds after year 2038 due to timestamp inconsistencies as
they wrap around, and could make the tools unusable altogether.

Change-Id: Iad828d38f84bd1824b83731ac3a3897da4b8b6d3

gnu/packages/base.scm

@@ -466,10 +466,6 @@ (define-public coreutils
                                    " test-renameatu"
                                    " test-utimensat")))
             '())
-      ,@(if (not (target-64bit?))
-          ;; Not all software is ready for 64bit time_t.
-          '(#:configure-flags (list "--disable-year2038"))
-          '())
       #:phases (modify-phases %standard-phases
                  (add-before 'build 'patch-shell-references
                    (lambda _