message: handle older macOS versions
  add logic to fallback to `localeIdentifier` if
  `currentLocale.languageCode` and `currentLocale.countryCode` are not
  available.
diff: @@ -23,20 +23,35 @@ use std::env;
  use objc::runtime::{Class, Object};
  pub fn set_locale_environment() {
  - let (language_code, country_code) = unsafe {
  + let locale_id = unsafe {
  let locale_class = Class::get("NSLocale").unwrap();
  let locale: *const Object = msg_send![locale_class, currentLocale];
  - msg_send![locale_class, release];
  + let _ : () = msg_send![locale_class, release];
  + // `localeIdentifier` returns extra metadata with the locale (including currency and
  + // collator) on newer versions of macOS. This is not a valid locale, so we use
  + // `languageCode` and `countryCode`, if they're available (macOS 10.12+):
  + // https://developer.apple.com/documentation/foundation/nslocale/1416263-localeidentifier?language=objc
  + // https://developer.apple.com/documentation/foundation/nslocale/1643060-countrycode?language=objc
  + // https://developer.apple.com/documentation/foundation/nslocale/1643026-languagecode?language=objc
  + let is_language_code_supported: bool = msg_send![locale, respondsToSelector:sel!(languageCode)];
  + let is_country_code_supported: bool = msg_send![locale, respondsToSelector:sel!(countryCode)];
  + let locale_id = if is_language_code_supported && is_country_code_supported {
  let language_code: *const Object = msg_send![locale, languageCode];
  let country_code: *const Object = msg_send![locale, countryCode];
  - msg_send![locale, release];
  let language_code_str = nsstring_as_str(language_code).to_owned();
  - msg_send![language_code, release];
  + let _ : () = msg_send![language_code, release];
  let country_code_str = nsstring_as_str(country_code).to_owned();
  - msg_send![country_code, release];
  - (language_code_str, country_code_str)
  + let _ : () = msg_send![country_code, release];
  + format!("{}_{}.UTF-8", &language_code_str, &country_code_str)
  + } else {
  + let identifier: *const Object = msg_send![locale, localeIdentifier];
  + let identifier_str = nsstring_as_str(identifier).to_owned();
  + let _ : () = msg_send![identifier, release];
  + identifier_str
  + };
  + let _ : () = msg_send![locale, release];
  + locale_id
  };
  - let locale_id = format!("{}_{}.UTF-8", &language_code, &country_code);
  // check if locale_id is valid
  let locale_c_str = CString::new(locale_id.to_owned()).unwrap();
  let locale_ptr = locale_c_str.as_ptr();
  