Win32: Defer change of timezone name encoding after 3.4

This change will be merged into 3.5 along with other encoding, command
line, environment variables, etc.

Revert following commits:

- bd831bcca5
  [Bug #20929] Win32: Use `wcsftime`

- 1c15f641cc
  [Bug #20929] Win32: Encode timezone name in UTF-8

- 78762b5218
  [Bug #20929] Fix `assert_zone_encoding`

test/ruby/test_time.rb

@@ -717,15 +717,13 @@ class TestTime < Test::Unit::TestCase
     assert_equal("2000-01-01 09:12:34 +091234", t2000.localtime(9*3600+12*60+34).inspect)
   end
 
-  FIXED_ZONE_ENCODING = (Encoding::UTF_8 if /mswin|mingw/.match?(RUBY_PLATFORM))
-
   def assert_zone_encoding(time)
     zone = time.zone
     assert_predicate(zone, :valid_encoding?)
     if zone.ascii_only?
       assert_equal(Encoding::US_ASCII, zone.encoding)
     else
-      enc = FIXED_ZONE_ENCODING || Encoding.find('locale')
+      enc = Encoding.default_internal || Encoding.find('locale')
       assert_equal(enc, zone.encoding)
     end
   end

time.c

@@ -31,10 +31,6 @@
 # include <sys/time.h>
 #endif
 
-#if defined(HAVE_LOCALE_H)
-# include <locale.h>
-#endif
-
 #include "id.h"
 #include "internal.h"
 #include "internal/array.h"
@@ -956,11 +952,7 @@ zone_str(const char *zone)
         str = rb_usascii_str_new(zone, len);
     }
     else {
-#if defined(_WIN32)
-        str = rb_utf8_str_new(zone, len);
-#else
         str = rb_enc_str_new(zone, len, rb_locale_encoding());
-#endif
     }
     return rb_fstring(str);
 }
@@ -1659,25 +1651,11 @@ localtime_with_gmtoff_zone(const time_t *t, struct tm *result, long *gmtoff, VAL
         if (zone) {
 #if defined(HAVE_TM_ZONE)
             *zone = zone_str(tm.tm_zone);
-#elif defined(_WIN32)
-            {
-                enum {tz_name_max = 32}; /* numberof(TIME_ZONE_INFORMATION::StandardName) */
-                WCHAR wbuf[tz_name_max + 1];
-                char cbuf[tz_name_max * 4 + 1];
-                size_t wlen = wcsftime(wbuf, numberof(wbuf), L"%Z", &tm);
-                DWORD clen = 0;
-                if (wlen > 0 && wlen < numberof(wbuf)) {
-                    clen = WideCharToMultiByte(CP_UTF8, 0, wbuf, wlen, cbuf, sizeof(cbuf), NULL, NULL);
-                }
-                if (clen > 0 && clen < sizeof(cbuf)) {
-                    cbuf[clen] = '\0';
-                    *zone = zone_str(cbuf);
-                }
-                else {
-                    *zone = zone_str(NULL);
-                }
-            }
 #elif defined(HAVE_TZNAME) && defined(HAVE_DAYLIGHT)
+# if defined(RUBY_MSVCRT_VERSION) && RUBY_MSVCRT_VERSION >= 140
+#  define tzname _tzname
+#  define daylight _daylight
+# endif
             /* this needs tzset or localtime, instead of localtime_r */
             *zone = zone_str(tzname[daylight && tm.tm_isdst]);
 #else

win32/Makefile.sub

@@ -785,7 +785,6 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define HAVE_STRUCT_TIMEVAL 1
 !if $(MSC_VER) >= 1900
 #define HAVE_STRUCT_TIMESPEC
-#define HAVE_LOCALE_H 1
 !endif
 !if $(MSC_VER) >= 1600
 #define HAVE_INTTYPES_H 1