Fix warning on macos from usage of deprecated Gestalt API

indra/llcommon/CMakeLists.txt

indra/llcommon/llsys.cpp

indra/llcommon/llsys_objc.h

indra/llcommon/llsys_objc.mm

indra/newview/skins/default/xui/da/language_settings.xml

indra/newview/skins/default/xui/de/language_settings.xml

indra/newview/skins/default/xui/en/language_settings.xml

indra/newview/skins/default/xui/es/language_settings.xml

indra/newview/skins/default/xui/fr/language_settings.xml

indra/newview/skins/default/xui/it/language_settings.xml

indra/newview/skins/default/xui/ja/language_settings.xml

indra/newview/skins/default/xui/pl/language_settings.xml

indra/newview/skins/default/xui/pt/language_settings.xml