localcharset: work around Mac OS X bug with UTF-8 and MB_CUR_MAX * lib/localcharset.c (locale_charset) [DARWIN7]: Return "ASCII" if the system reports "UTF-8" and MB_CUR_MAX <= 1, as these two values are incompatible. Problem reported by Max Horn. For more discussion, please see <http://lists.gnu.org/archive/html/bug-gnulib/2012-09/msg00061.html>.