New optional ZONE arg for format-time-string etc.

This simplifies time conversions in other time zones.
It also prevents display-time-world tampering with TZ (Bug#21020).
* admin/admin.el (add-release-logs):
Use improved add-log-time-format API.
* admin/merge-gnulib (GNULIB_MODULES): Add time_rz, timegm.
(GNULIB_TOOL_FLAGS): Avoid flexmember, setenv, unsetenv.
* configure.ac (tzalloc): Remove test for this, since
Emacs no longer uses HAVE_TZALLOC directly.
* doc/lispref/os.texi (Time of Day, Time Conversion)
(Time Parsing):
* etc/NEWS: Document the new behavior.
Merge from gnulib, incorporating:
2015-07-25 strftime: fix newly-introduced bug on Solaris
2015-07-23 fprintftime, strftime: use timezone_t args
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* lib/strftime.c, lib/strftime.h, lib/time.in.h, m4/sys_time_h.m4:
* m4/time_h.m4:
Update from gnulib.
* lib/time_rz.c, lib/timegm.c, m4/time_rz.m4, m4/timegm.m4:
New files from gnulib.
* lisp/time-stamp.el (time-stamp-string):
* lisp/time.el (display-time-world-list)
(display-time-world-display):
Use new API, with time zone arg.
* lisp/time.el (display-time-world-display):
Fix race when current-time advances while we're running.
* lisp/vc/add-log.el (add-log-iso8601-time-zone)
(add-log-iso8601-time-string): Accept optional time zone arg.
* lisp/vc/add-log.el (add-change-log-entry):
* lisp/vc/log-edit.el (log-edit-changelog-ours-p): Use new arg.
* nt/gnulib.mk: Propagate lib/gnulib.mk changes here.
Add rules for the time module, since they're now needed
for tzalloc etc.
* src/conf_post.h (getenv_TZ, setenv_TZ): New macros.
(emacs_getenv_TZ, emacs_setenv_TZ): New decls.
* src/editfns.c: Include errno.h.
(set_time_zone_rule): Omit unnecessary forward decl.
(initial_tz): Remove, replacing with ...
(local_tz, wall_clock_tz, utc_tz): New static vars and constants.
(tzeqlen): New constant; prefer it to (sizeof "TZ=" - 1).
(emacs_localtime_rz, emacs_mktime_z, xtzalloc, xtzfree)
(tzlookup): New static functions.
(init_editfns): New arg DUMPING.  All uses changed.
(init_editfns): Omit most initialization if dumping, not if
!initialized.  Initialize wall_clock_tz and local_tz.
(emacs_nmemftime, format_time_string): Time zone argument can now
be any time zone, not just a boolean for UTC or local time.  All
callers changed.
(Fformat_time_string, Fencode_time, Fcurrent_time_string)
(Fcurrent_time_zone): New optional arg ZONE.
(Fdecode_time, Fset_time_zone_rule): ZONE arg can now also take
the same form as with the other new additions.
(decode_time_zone): Remove; no longer needed.
(tzvalbuf): Now file-scope.
(emacs_getenv_TZ, emacs_setenv_TZ): New functions.
(syms_of_editfns): Define Qwall.
* src/editfns.c (mktime_z) [!HAVE_TZALLOC]:
* src/systime.h (mktime_z, timezone_t, tzalloc, tzfree)
[!HAVE_TZALLOC]:
Remove; now supplied by gnulib.
* src/emacs.c (main):
* src/lisp.h (init_editfns): Adjust to init_editfns API change.

5 files changed, 83 insertions, 9 deletions

diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index 0425d02241a..cf71d7eb187 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -98,6 +98,7 @@ AC_DEFUN([gl_EARLY],
   # Code from module memrchr:
   # Code from module mkostemp:
   # Code from module mktime:
+  # Code from module mktime-internal:
   # Code from module multiarch:
   # Code from module nocrash:
   # Code from module openat-h:
@@ -141,13 +142,14 @@ AC_DEFUN([gl_EARLY],
   # Code from module tempname:
   # Code from module time:
   # Code from module time_r:
+  # Code from module time_rz:
+  # Code from module timegm:
   # Code from module timer-time:
   # Code from module timespec:
   # Code from module timespec-add:
   # Code from module timespec-sub:
   # Code from module u64:
   # Code from module unistd:
-  # Code from module unsetenv:
   # Code from module update-copyright:
   # Code from module utimens:
   # Code from module vararrays:
@@ -385,15 +387,20 @@ AC_DEFUN([gl_INIT],
     gl_PREREQ_TIME_R
   fi
   gl_TIME_MODULE_INDICATOR([time_r])
+  gl_TIME_RZ
+  if test "$HAVE_TIMEZONE_T" = 0; then
+    AC_LIBOBJ([time_rz])
+  fi
+  gl_TIME_MODULE_INDICATOR([time_rz])
+  gl_FUNC_TIMEGM
+  if test $HAVE_TIMEGM = 0 || test $REPLACE_TIMEGM = 1; then
+    AC_LIBOBJ([timegm])
+    gl_PREREQ_TIMEGM
+  fi
+  gl_TIME_MODULE_INDICATOR([timegm])
   gl_TIMER_TIME
   gl_TIMESPEC
   gl_UNISTD_H
-  gl_FUNC_UNSETENV
-  if test $HAVE_UNSETENV = 0 || test $REPLACE_UNSETENV = 1; then
-    AC_LIBOBJ([unsetenv])
-    gl_PREREQ_UNSETENV
-  fi
-  gl_STDLIB_MODULE_INDICATOR([unsetenv])
   gl_UTIMENS
   AC_C_VARARRAYS
   gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b=false
@@ -404,6 +411,7 @@ AC_DEFUN([gl_INIT],
   gl_gnulib_enabled_getgroups=false
   gl_gnulib_enabled_be453cec5eecf5731a274f2de7f2db36=false
   gl_gnulib_enabled_a9786850e999ae65a836a6041e8e5ed1=false
+  gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31=false
   gl_gnulib_enabled_03e0aaad4cb89ca757653bd367a6ccb7=false
   gl_gnulib_enabled_pathmax=false
   gl_gnulib_enabled_6099e9737f757db36c47fa9d9f02e88c=false
@@ -506,6 +514,17 @@ AC_DEFUN([gl_INIT],
       fi
     fi
   }
+  func_gl_gnulib_m4code_5264294aa0a5557541b53c8c741f7f31 ()
+  {
+    if ! $gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31; then
+      gl_FUNC_MKTIME_INTERNAL
+      if test $REPLACE_MKTIME = 1; then
+        AC_LIBOBJ([mktime])
+        gl_PREREQ_MKTIME
+      fi
+      gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31=true
+    fi
+  }
   func_gl_gnulib_m4code_03e0aaad4cb89ca757653bd367a6ccb7 ()
   {
     if ! $gl_gnulib_enabled_03e0aaad4cb89ca757653bd367a6ccb7; then
@@ -653,6 +672,9 @@ AC_DEFUN([gl_INIT],
   if { test $HAVE_DECL_STRTOUMAX = 0 || test $REPLACE_STRTOUMAX = 1; } && test $ac_cv_type_unsigned_long_long_int = yes; then
     func_gl_gnulib_m4code_strtoull
   fi
+  if test $HAVE_TIMEGM = 0 || test $REPLACE_TIMEGM = 1; then
+    func_gl_gnulib_m4code_5264294aa0a5557541b53c8c741f7f31
+  fi
   m4_pattern_allow([^gl_GNULIB_ENABLED_])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_260941c0e5dc67ec9e87d1fb321c300b], [$gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_dirfd], [$gl_gnulib_enabled_dirfd])
@@ -662,6 +684,7 @@ AC_DEFUN([gl_INIT],
   AM_CONDITIONAL([gl_GNULIB_ENABLED_getgroups], [$gl_gnulib_enabled_getgroups])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_be453cec5eecf5731a274f2de7f2db36], [$gl_gnulib_enabled_be453cec5eecf5731a274f2de7f2db36])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_a9786850e999ae65a836a6041e8e5ed1], [$gl_gnulib_enabled_a9786850e999ae65a836a6041e8e5ed1])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_5264294aa0a5557541b53c8c741f7f31], [$gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_03e0aaad4cb89ca757653bd367a6ccb7], [$gl_gnulib_enabled_03e0aaad4cb89ca757653bd367a6ccb7])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_pathmax], [$gl_gnulib_enabled_pathmax])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_6099e9737f757db36c47fa9d9f02e88c], [$gl_gnulib_enabled_6099e9737f757db36c47fa9d9f02e88c])
@@ -938,6 +961,8 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/tempname.h
   lib/time.in.h
   lib/time_r.c
+  lib/time_rz.c
+  lib/timegm.c
   lib/timespec-add.c
   lib/timespec-sub.c
   lib/timespec.c
@@ -946,7 +971,6 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/u64.h
   lib/unistd.c
   lib/unistd.in.h
-  lib/unsetenv.c
   lib/utimens.c
   lib/utimens.h
   lib/verify.h
@@ -1011,7 +1035,6 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/readlink.m4
   m4/readlinkat.m4
   m4/secure_getenv.m4
-  m4/setenv.m4
   m4/sha1.m4
   m4/sha256.m4
   m4/sha512.m4
@@ -1043,6 +1066,8 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/tempname.m4
   m4/time_h.m4
   m4/time_r.m4
+  m4/time_rz.m4
+  m4/timegm.m4
   m4/timer_time.m4
   m4/timespec.m4
   m4/tm_gmtoff.m4
diff --git a/m4/sys_time_h.m4 b/m4/sys_time_h.m4
index 50133b9ff9a..28c8b1acbba 100644
--- a/m4/sys_time_h.m4
+++ b/m4/sys_time_h.m4
@@ -105,6 +105,7 @@ AC_DEFUN([gl_HEADER_SYS_TIME_H_DEFAULTS],
   HAVE_GETTIMEOFDAY=1;       AC_SUBST([HAVE_GETTIMEOFDAY])
   HAVE_STRUCT_TIMEVAL=1;     AC_SUBST([HAVE_STRUCT_TIMEVAL])
   HAVE_SYS_TIME_H=1;         AC_SUBST([HAVE_SYS_TIME_H])
+  HAVE_TIMEZONE_T=0;         AC_SUBST([HAVE_TIMEZONE_T])
   REPLACE_GETTIMEOFDAY=0;    AC_SUBST([REPLACE_GETTIMEOFDAY])
   REPLACE_STRUCT_TIMEVAL=0;  AC_SUBST([REPLACE_STRUCT_TIMEVAL])
 ])
diff --git a/m4/time_h.m4 b/m4/time_h.m4
index d9c41a48f33..754b469a0d9 100644
--- a/m4/time_h.m4
+++ b/m4/time_h.m4
@@ -109,6 +109,7 @@ AC_DEFUN([gl_HEADER_TIME_H_DEFAULTS],
   GNULIB_STRPTIME=0;                     AC_SUBST([GNULIB_STRPTIME])
   GNULIB_TIMEGM=0;                       AC_SUBST([GNULIB_TIMEGM])
   GNULIB_TIME_R=0;                       AC_SUBST([GNULIB_TIME_R])
+  GNULIB_TIME_RZ=0;                      AC_SUBST([GNULIB_TIME_RZ])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_DECL_LOCALTIME_R=1;               AC_SUBST([HAVE_DECL_LOCALTIME_R])
   HAVE_NANOSLEEP=1;                      AC_SUBST([HAVE_NANOSLEEP])
diff --git a/m4/time_rz.m4 b/m4/time_rz.m4
new file mode 100644
index 00000000000..0c1f2c3736c
--- /dev/null
+++ b/m4/time_rz.m4
@@ -0,0 +1,21 @@
+dnl Time zone functions: tzalloc, localtime_rz, etc.
+
+dnl Copyright (C) 2015 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN([gl_TIME_RZ],
+[
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
+  AC_REQUIRE([AC_STRUCT_TIMEZONE])
+  AC_CHECK_FUNCS_ONCE([tzset])
+
+  AC_CHECK_TYPES([timezone_t], [], [], [[#include <time.h>]])
+  if test "$ac_cv_type_timezone_t" = yes; then
+    HAVE_TIMEZONE_T=1
+  fi
+])
diff --git a/m4/timegm.m4 b/m4/timegm.m4
new file mode 100644
index 00000000000..8e68b99baa2
--- /dev/null
+++ b/m4/timegm.m4
@@ -0,0 +1,26 @@
+# timegm.m4 serial 11
+dnl Copyright (C) 2003, 2007, 2009-2015 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_TIMEGM],
+[
+  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_MKTIME])
+  REPLACE_TIMEGM=0
+  AC_CHECK_FUNCS_ONCE([timegm])
+  if test $ac_cv_func_timegm = yes; then
+    if test $gl_cv_func_working_mktime = no; then
+      # Assume that timegm is buggy if mktime is.
+      REPLACE_TIMEGM=1
+    fi
+  else
+    HAVE_TIMEGM=0
+  fi
+])
+
+# Prerequisites of lib/timegm.c.
+AC_DEFUN([gl_PREREQ_TIMEGM], [
+  :
+])