maintainer-feedback requested: [Bug 240517] [PATCH] devel/glib20: syscall flood on every time*() function call

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Bug 240517: [PATCH] devel/glib20: syscall flood on every time*() function call
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=240517



--- Description ---
truss show that GTK app do many times:
...
27100: openat(AT_FDCWD,"/etc/localtime",O_RDONLY,00) = 114 (0x72)
27100: fstat(114,{ mode=-r--r--r-- ,inode=1845941,size=1518,blksize=32768 }) =
0 (0x0)
27100: mmap(0x0,1518,PROT_READ,MAP_PRIVATE,114,0x0) = 34458873856 (0x805e8b000)
27100: close(114)				 = 0 (0x0)
27100: munmap(0x805e8b000,1518) 		 = 0 (0x0)
...

I found article:
https://blog.packagecloud.io/eng/2017/02/21/set-environment-variable-save-thous
ands-of-system-calls/
and try to set:
env TZ=":/etc/localtime" truss -fD geany
or
env TZ="Europe/Moscow" truss -fD geany
without success.

I discovered that glib time zone cache is does not work properly:
==========================================================
GDateTime *
g_date_time_new_from_unix_local (gint64 t)
{
  GDateTime *datetime;
  GTimeZone *local;

  local = g_time_zone_new_local ();
  datetime = g_date_time_new_from_unix (local, t);
  g_time_zone_unref (local);

  return datetime;
}

GTimeZone *
g_time_zone_new_local (void)
{
  return g_time_zone_new (getenv ("TZ"));
}
==========================================================

g_time_zone_new() load and add time zone to cache if arg is not NULL.
g_time_zone_unref() - remove time zone from cache.
As you can see time zone in most cases removed from cache after short time.

Patch add_ref() for time zone "getenv ("TZ")" and "UTC", all other calls
g_time_zone_new() leave without changes.
After apply patch and set TZ=":/etc/localtime" / TZ="Europe/Moscow" no more
syscall flood happen.