* lib/setlocale.c (search): Optimize away a redundant strcmp()
invocation.
(locales_with_principal_territory): New array.
(langcmp, get_main_locale_with_same_language): New functions.
(locales_with_principal_language): New array.
(terrcmp, get_main_locale_with_same_territory): New functions.
(rpl_setlocale): When setlocale_single failed, try again with a locale
that is more likely to exist. Don't warn if the environment variable
SETLOCALE_VERBOSE is not set.