Bug 1856428 - MacOS Sonoma doesn't return correct timezone. r=anba

Import from https://unicode-org.atlassian.net/browse/ICU-22541
(unicode-org/icu#2669).

Differential Revision: https://phabricator.services.mozilla.com/D191013

UltraBlame original commit: 91657cb1296c904004ace38877b9ca91f502be3f

intl/icu-patches/bug-1856428-ICU-22541.diff

@@ -0,0 +1,399 @@
+#
+Fix
+MacOS
+14
+default
+timezone
+issue
+#
+#
+ICU
+bug
+:
+https
+:
+/
+/
+unicode
+-
+org
+.
+atlassian
+.
+net
+/
+browse
+/
+ICU
+-
+22541
+diff
+-
+-
+git
+a
+/
+intl
+/
+icu
+/
+source
+/
+common
+/
+putil
+.
+cpp
+b
+/
+intl
+/
+icu
+/
+source
+/
+common
+/
+putil
+.
+cpp
+-
+-
+-
+a
+/
+intl
+/
+icu
+/
+source
+/
+common
+/
+putil
+.
+cpp
++
++
++
+b
+/
+intl
+/
+icu
+/
+source
+/
+common
+/
+putil
+.
+cpp
+-
+1170
+16
++
+1170
+31
+uprv_tzname
+(
+int
+n
+)
+This
+is
+a
+trick
+to
+look
+at
+the
+name
+of
+the
+link
+to
+get
+the
+Olson
+ID
+because
+the
+tzfile
+contents
+is
+underspecified
+.
+This
+isn
+'
+t
+guaranteed
+to
+work
+because
+it
+may
+not
+be
+a
+symlink
+.
+*
+/
+char
+*
+ret
+=
+realpath
+(
+TZDEFAULT
+gTimeZoneBuffer
+)
+;
+if
+(
+ret
+!
+=
+nullptr
+&
+&
+uprv_strcmp
+(
+TZDEFAULT
+gTimeZoneBuffer
+)
+!
+=
+0
+)
+{
+int32_t
+tzZoneInfoTailLen
+=
+uprv_strlen
+(
+TZZONEINFOTAIL
+)
+;
+const
+char
+*
+tzZoneInfoTailPtr
+=
+uprv_strstr
+(
+gTimeZoneBuffer
+TZZONEINFOTAIL
+)
+;
++
+/
+/
+MacOS14
+has
+the
+realpath
+as
+something
+like
++
+/
+/
+/
+usr
+/
+share
+/
+zoneinfo
+.
+default
+/
+Australia
+/
+Melbourne
++
+/
+/
+which
+will
+not
+have
+"
+/
+zoneinfo
+/
+"
+in
+the
+path
+.
++
+/
+/
+Therefore
+if
+we
+fail
+we
+fall
+back
+to
+read
+the
+link
+which
+is
++
+/
+/
+/
+var
+/
+db
+/
+timezone
+/
+zoneinfo
+/
+Australia
+/
+Melbourne
++
+/
+/
+We
+also
+fall
+back
+to
+reading
+the
+link
+if
+the
+realpath
+leads
+to
+something
+like
++
+/
+/
+/
+usr
+/
+share
+/
+zoneinfo
+/
+posixrules
++
+if
+(
+tzZoneInfoTailPtr
+=
+=
+nullptr
+|
+|
++
+uprv_strcmp
+(
+tzZoneInfoTailPtr
++
+tzZoneInfoTailLen
+"
+posixrules
+"
+)
+=
+=
+0
+)
+{
++
+ssize_t
+size
+=
+readlink
+(
+TZDEFAULT
+gTimeZoneBuffer
+sizeof
+(
+gTimeZoneBuffer
+)
+-
+1
+)
+;
++
+if
+(
+size
+>
+0
+)
+{
++
+gTimeZoneBuffer
+[
+size
+]
+=
+0
+;
++
+tzZoneInfoTailPtr
+=
+uprv_strstr
+(
+gTimeZoneBuffer
+TZZONEINFOTAIL
+)
+;
++
+}
++
+}
+if
+(
+tzZoneInfoTailPtr
+!
+=
+nullptr
+)
+{
+tzZoneInfoTailPtr
++
+=
+tzZoneInfoTailLen
+;
+skipZoneIDPrefix
+(
+&
+tzZoneInfoTailPtr
+)
+;
+if
+(
+isValidOlsonID
+(
+tzZoneInfoTailPtr
+)
+)
+{
+return
+(
+gTimeZoneBufferPtr
+=
+tzZoneInfoTailPtr
+)
+;
+}
+}
+}
+else
+{