Add "SHIFT_JIS" as an accepted encoding name for locale checking.

When locale is "ja_JP.SJIS", nl_langinfo(CODESET) returns "SHIFT_JIS"
on some platforms, at least on RedHat Linux. So the encoding/locale
match table (encoding_match_list) needs the entry. Otherwise client
encoding is set to SQL_ASCII.

Back patch to all supported branches.

src/port/chklocale.c

@@ -162,6 +162,7 @@ static const struct encoding_match encoding_match_list[] = {
 	{PG_SJIS, "SJIS"},
 	{PG_SJIS, "PCK"},
 	{PG_SJIS, "CP932"},
+	{PG_SJIS, "SHIFT_JIS"},
 
 	{PG_BIG5, "BIG5"},
 	{PG_BIG5, "BIG5HKSCS"},