* cygheap.cc (cygheap_init): Default locale.charset to "UTF-8".

* dcrt0.cc (dll_crt0_1): Call setlocale (LC_CTYPE, "") here, just
	before resetting application locale to "C".
	* environ.cc (environ_init): Drop code setting locale here.
	* syscalls.cc (check_codepage): Break out check for required codepage
	from internal_setlocale.
	(internal_setlocale): Just convert CWD and $PATH from old charset to
	new charset and set internal charset.
	(setlocale): Change accordingly.  Don't require LC_ALL or LC_CTYPE to
	store old locale value.  Always call internal_setlocale if charset
	changed due to locale environment changes.

winsup/cygwin/cygheap.cc

@@ -164,7 +164,7 @@ cygheap_init ()
       /* Default locale settings. */
       cygheap->locale.mbtowc = __utf8_mbtowc;
       cygheap->locale.wctomb = __utf8_wctomb;
-      strcpy (cygheap->locale.charset, "ASCII");
+      strcpy (cygheap->locale.charset, "UTF-8");
       /* Set umask to a sane default. */
       cygheap->umask = 022;
     }