Index: libc/locale/locale.c
===================================================================
RCS file: /cvs/src/src/newlib/libc/locale/locale.c,v
retrieving revision 1.46
diff -u -r1.46 locale.c
--- libc/locale/locale.c	11 May 2010 20:40:14 -0000	1.46
+++ libc/locale/locale.c	9 Nov 2010 21:05:31 -0000
@@ -845,16 +845,19 @@
       __wctomb = l_wctomb;
       __mbtowc = l_mbtowc;
       __set_ctype (charset);
-      /* Check for the language part of the locale specifier.  In case
-         of "ja", "ko", or "zh", assume the use of CJK fonts, unless the
-	 "@cjknarrow" modifier has been specifed.
-	 The result is stored in lc_ctype_cjk_lang and tested in wcwidth()
-	 to figure out the width to return (1 or 2) for the "CJK Ambiguous
-	 Width" category of characters. */
+      /* Determine the width for the "CJK Ambiguous Width" category of
+         characters. This is used in wcwidth().
+         Assume single width for single-byte charsets, and double width for
+         multi-byte charsets other than UTF-8. For UTF-8, use double width for
+         the East Asian locales ("ja", "ko", "zh"), and single width for
+         everything else. Single width can also be forced with the 
+         "@cjknarrow" modifier. */
       lc_ctype_cjk_lang = !cjknarrow
-			  && ((strncmp (locale, "ja", 2) == 0
+			  && mbc_max > 1
+			  && (charset[0] != 'U'
+			      || strncmp (locale, "ja", 2) == 0
 			      || strncmp (locale, "ko", 2) == 0
-			      || strncmp (locale, "zh", 2) == 0));
+			      || strncmp (locale, "zh", 2) == 0);
 #ifdef __HAVE_LOCALE_INFO__
       ret = __ctype_load_locale (locale, (void *) l_wctomb, charset, mbc_max);
 #endif /* __HAVE_LOCALE_INFO__ */