diff --git a/configure b/configure
index 5c38149a3d..70d8aa649d 100755
--- a/configure
+++ b/configure
@@ -12970,7 +12970,7 @@ fi
 LIBS_including_readline="$LIBS"
 LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
 
-for ac_func in cbrt clock_gettime dlopen fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll pstat pthread_is_threaded_np readlink setproctitle setsid shm_open symlink sync_file_range towlower utime utimes wcstombs wcstombs_l
+for ac_func in cbrt clock_gettime dlopen fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll pstat pthread_is_threaded_np readlink setproctitle setsid shm_open symlink sync_file_range utime utimes wcstombs_l
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/configure.in b/configure.in
index 176b29a792..cdf11bf673 100644
--- a/configure.in
+++ b/configure.in
@@ -1399,7 +1399,7 @@ PGAC_FUNC_WCSTOMBS_L
 LIBS_including_readline="$LIBS"
 LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
 
-AC_CHECK_FUNCS([cbrt clock_gettime dlopen fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll pstat pthread_is_threaded_np readlink setproctitle setsid shm_open symlink sync_file_range towlower utime utimes wcstombs wcstombs_l])
+AC_CHECK_FUNCS([cbrt clock_gettime dlopen fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll pstat pthread_is_threaded_np readlink setproctitle setsid shm_open symlink sync_file_range utime utimes wcstombs_l])
 
 AC_REPLACE_FUNCS(fseeko)
 case $host_os in
diff --git a/src/backend/regex/regc_pg_locale.c b/src/backend/regex/regc_pg_locale.c
index 6982879688..b2122e9e8f 100644
--- a/src/backend/regex/regc_pg_locale.c
+++ b/src/backend/regex/regc_pg_locale.c
@@ -268,7 +268,6 @@ pg_set_regex_collation(Oid collation)
 			pg_regex_strategy = PG_REGEX_LOCALE_ICU;
 		else
 #endif
-#ifdef USE_WIDE_UPPER_LOWER
 		if (GetDatabaseEncoding() == PG_UTF8)
 		{
 			if (pg_regex_locale)
@@ -277,7 +276,6 @@ pg_set_regex_collation(Oid collation)
 				pg_regex_strategy = PG_REGEX_LOCALE_WIDE;
 		}
 		else
-#endif							/* USE_WIDE_UPPER_LOWER */
 		{
 			if (pg_regex_locale)
 				pg_regex_strategy = PG_REGEX_LOCALE_1BYTE_L;
@@ -298,16 +296,14 @@ pg_wc_isdigit(pg_wchar c)
 			return (c <= (pg_wchar) 127 &&
 					(pg_char_properties[c] & PG_ISDIGIT));
 		case PG_REGEX_LOCALE_WIDE:
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswdigit((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isdigit((unsigned char) c));
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswdigit_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -336,16 +332,14 @@ pg_wc_isalpha(pg_wchar c)
 			return (c <= (pg_wchar) 127 &&
 					(pg_char_properties[c] & PG_ISALPHA));
 		case PG_REGEX_LOCALE_WIDE:
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswalpha((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isalpha((unsigned char) c));
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswalpha_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -374,16 +368,14 @@ pg_wc_isalnum(pg_wchar c)
 			return (c <= (pg_wchar) 127 &&
 					(pg_char_properties[c] & PG_ISALNUM));
 		case PG_REGEX_LOCALE_WIDE:
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswalnum((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isalnum((unsigned char) c));
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswalnum_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -412,16 +404,14 @@ pg_wc_isupper(pg_wchar c)
 			return (c <= (pg_wchar) 127 &&
 					(pg_char_properties[c] & PG_ISUPPER));
 		case PG_REGEX_LOCALE_WIDE:
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswupper((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isupper((unsigned char) c));
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswupper_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -450,16 +440,14 @@ pg_wc_islower(pg_wchar c)
 			return (c <= (pg_wchar) 127 &&
 					(pg_char_properties[c] & PG_ISLOWER));
 		case PG_REGEX_LOCALE_WIDE:
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswlower((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					islower((unsigned char) c));
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswlower_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -488,16 +476,14 @@ pg_wc_isgraph(pg_wchar c)
 			return (c <= (pg_wchar) 127 &&
 					(pg_char_properties[c] & PG_ISGRAPH));
 		case PG_REGEX_LOCALE_WIDE:
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswgraph((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isgraph((unsigned char) c));
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswgraph_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -526,16 +512,14 @@ pg_wc_isprint(pg_wchar c)
 			return (c <= (pg_wchar) 127 &&
 					(pg_char_properties[c] & PG_ISPRINT));
 		case PG_REGEX_LOCALE_WIDE:
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswprint((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isprint((unsigned char) c));
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswprint_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -564,16 +548,14 @@ pg_wc_ispunct(pg_wchar c)
 			return (c <= (pg_wchar) 127 &&
 					(pg_char_properties[c] & PG_ISPUNCT));
 		case PG_REGEX_LOCALE_WIDE:
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswpunct((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					ispunct((unsigned char) c));
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswpunct_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -602,16 +584,14 @@ pg_wc_isspace(pg_wchar c)
 			return (c <= (pg_wchar) 127 &&
 					(pg_char_properties[c] & PG_ISSPACE));
 		case PG_REGEX_LOCALE_WIDE:
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswspace((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isspace((unsigned char) c));
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswspace_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -644,10 +624,8 @@ pg_wc_toupper(pg_wchar c)
 			/* force C behavior for ASCII characters, per comments above */
 			if (c <= (pg_wchar) 127)
 				return pg_ascii_toupper((unsigned char) c);
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return towupper((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			/* force C behavior for ASCII characters, per comments above */
@@ -657,7 +635,7 @@ pg_wc_toupper(pg_wchar c)
 				return toupper((unsigned char) c);
 			return c;
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return towupper_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
@@ -690,10 +668,8 @@ pg_wc_tolower(pg_wchar c)
 			/* force C behavior for ASCII characters, per comments above */
 			if (c <= (pg_wchar) 127)
 				return pg_ascii_tolower((unsigned char) c);
-#ifdef USE_WIDE_UPPER_LOWER
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return towlower((wint_t) c);
-#endif
 			/* FALL THRU */
 		case PG_REGEX_LOCALE_1BYTE:
 			/* force C behavior for ASCII characters, per comments above */
@@ -703,7 +679,7 @@ pg_wc_tolower(pg_wchar c)
 				return tolower((unsigned char) c);
 			return c;
 		case PG_REGEX_LOCALE_WIDE_L:
-#if defined(HAVE_LOCALE_T) && defined(USE_WIDE_UPPER_LOWER)
+#ifdef HAVE_LOCALE_T
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return towlower_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
diff --git a/src/backend/tsearch/regis.c b/src/backend/tsearch/regis.c
index 2b89f596f0..4a799f2585 100644
--- a/src/backend/tsearch/regis.c
+++ b/src/backend/tsearch/regis.c
@@ -178,7 +178,6 @@ RS_free(Regis *r)
 	r->node = NULL;
 }
 
-#ifdef USE_WIDE_UPPER_LOWER
 static bool
 mb_strchr(char *str, char *c)
 {
@@ -209,10 +208,6 @@ mb_strchr(char *str, char *c)
 
 	return res;
 }
-#else
-#define mb_strchr(s,c)	( (strchr((s),*(c)) == NULL) ? false : true )
-#endif
-
 
 bool
 RS_execute(Regis *r, char *str)
diff --git a/src/backend/tsearch/ts_locale.c b/src/backend/tsearch/ts_locale.c
index 1aa3e23733..7a6f0bc722 100644
--- a/src/backend/tsearch/ts_locale.c
+++ b/src/backend/tsearch/ts_locale.c
@@ -21,8 +21,6 @@
 static void tsearch_readline_callback(void *arg);
 
 
-#ifdef USE_WIDE_UPPER_LOWER
-
 int
 t_isdigit(const char *ptr)
 {
@@ -86,7 +84,6 @@ t_isprint(const char *ptr)
 
 	return iswprint((wint_t) character[0]);
 }
-#endif							/* USE_WIDE_UPPER_LOWER */
 
 
 /*
@@ -244,17 +241,12 @@ char *
 lowerstr_with_len(const char *str, int len)
 {
 	char	   *out;
-
-#ifdef USE_WIDE_UPPER_LOWER
 	Oid			collation = DEFAULT_COLLATION_OID;	/* TODO */
 	pg_locale_t mylocale = 0;	/* TODO */
-#endif
 
 	if (len == 0)
 		return pstrdup("");
 
-#ifdef USE_WIDE_UPPER_LOWER
-
 	/*
 	 * Use wide char code only when max encoding length > 1 and ctype != C.
 	 * Some operating systems fail with multi-byte encodings and a C locale.
@@ -300,7 +292,6 @@ lowerstr_with_len(const char *str, int len)
 		Assert(wlen < len);
 	}
 	else
-#endif							/* USE_WIDE_UPPER_LOWER */
 	{
 		const char *ptr = str;
 		char	   *outptr;
diff --git a/src/backend/tsearch/wparser_def.c b/src/backend/tsearch/wparser_def.c
index e841a1ccf0..c118357336 100644
--- a/src/backend/tsearch/wparser_def.c
+++ b/src/backend/tsearch/wparser_def.c
@@ -241,11 +241,9 @@ typedef struct TParser
 	/* string and position information */
 	char	   *str;			/* multibyte string */
 	int			lenstr;			/* length of mbstring */
-#ifdef USE_WIDE_UPPER_LOWER
 	wchar_t    *wstr;			/* wide character string */
 	pg_wchar   *pgwstr;			/* wide character string for C-locale */
 	bool		usewide;
-#endif
 
 	/* State of parse */
 	int			charmaxlen;
@@ -294,8 +292,6 @@ TParserInit(char *str, int len)
 	prs->str = str;
 	prs->lenstr = len;
 
-#ifdef USE_WIDE_UPPER_LOWER
-
 	/*
 	 * Use wide char code only when max encoding length > 1.
 	 */
@@ -323,7 +319,6 @@ TParserInit(char *str, int len)
 	}
 	else
 		prs->usewide = false;
-#endif
 
 	prs->state = newTParserPosition(NULL);
 	prs->state->state = TPS_Base;
@@ -360,15 +355,12 @@ TParserCopyInit(const TParser *orig)
 	prs->charmaxlen = orig->charmaxlen;
 	prs->str = orig->str + orig->state->posbyte;
 	prs->lenstr = orig->lenstr - orig->state->posbyte;
-
-#ifdef USE_WIDE_UPPER_LOWER
 	prs->usewide = orig->usewide;
 
 	if (orig->pgwstr)
 		prs->pgwstr = orig->pgwstr + orig->state->poschar;
 	if (orig->wstr)
 		prs->wstr = orig->wstr + orig->state->poschar;
-#endif
 
 	prs->state = newTParserPosition(NULL);
 	prs->state->state = TPS_Base;
@@ -393,12 +385,10 @@ TParserClose(TParser *prs)
 		prs->state = ptr;
 	}
 
-#ifdef USE_WIDE_UPPER_LOWER
 	if (prs->wstr)
 		pfree(prs->wstr);
 	if (prs->pgwstr)
 		pfree(prs->pgwstr);
-#endif
 
 #ifdef WPARSER_TRACE
 	fprintf(stderr, "closing parser\n");
@@ -437,8 +427,6 @@ TParserCopyClose(TParser *prs)
  *	- if locale is C then we use pgwstr instead of wstr.
  */
 
-#ifdef USE_WIDE_UPPER_LOWER
-
 #define p_iswhat(type)														\
 static int																	\
 p_is##type(TParser *prs) {													\
@@ -536,31 +524,6 @@ p_iseq(TParser *prs, char c)
 	Assert(prs->state);
 	return ((prs->state->charlen == 1 && *(prs->str + prs->state->posbyte) == c)) ? 1 : 0;
 }
-#else							/* USE_WIDE_UPPER_LOWER */
-
-#define p_iswhat(type)														\
-static int																	\
-p_is##type(TParser *prs) {													\
-	Assert( prs->state );													\
-	return is##type( (unsigned char)*( prs->str + prs->state->posbyte ) );	\
-}	\
-																			\
-static int																	\
-p_isnot##type(TParser *prs) {												\
-	return !p_is##type(prs);												\
-}
-
-
-static int
-p_iseq(TParser *prs, char c)
-{
-	Assert(prs->state);
-	return (*(prs->str + prs->state->posbyte) == c) ? 1 : 0;
-}
-
-p_iswhat(alnum)
-p_iswhat(alpha)
-#endif							/* USE_WIDE_UPPER_LOWER */
 
 p_iswhat(digit)
 p_iswhat(lower)
@@ -785,8 +748,6 @@ p_isspecial(TParser *prs)
 	if (pg_dsplen(prs->str + prs->state->posbyte) == 0)
 		return 1;
 
-#ifdef USE_WIDE_UPPER_LOWER
-
 	/*
 	 * Unicode Characters in the 'Mark, Spacing Combining' Category That
 	 * characters are not alpha although they are not breakers of word too.
@@ -1050,7 +1011,6 @@ p_isspecial(TParser *prs)
 				StopHigh = StopMiddle;
 		}
 	}
-#endif
 
 	return 0;
 }
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 2bf484cda3..7877af2d6b 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -1565,7 +1565,6 @@ str_tolower(const char *buff, size_t nbytes, Oid collid)
 		else
 #endif
 		{
-#ifdef USE_WIDE_UPPER_LOWER
 			if (pg_database_encoding_max_length() > 1)
 			{
 				wchar_t    *workspace;
@@ -1604,7 +1603,6 @@ str_tolower(const char *buff, size_t nbytes, Oid collid)
 				pfree(workspace);
 			}
 			else
-#endif							/* USE_WIDE_UPPER_LOWER */
 			{
 				char	   *p;
 
@@ -1689,7 +1687,6 @@ str_toupper(const char *buff, size_t nbytes, Oid collid)
 		else
 #endif
 		{
-#ifdef USE_WIDE_UPPER_LOWER
 			if (pg_database_encoding_max_length() > 1)
 			{
 				wchar_t    *workspace;
@@ -1728,7 +1725,6 @@ str_toupper(const char *buff, size_t nbytes, Oid collid)
 				pfree(workspace);
 			}
 			else
-#endif							/* USE_WIDE_UPPER_LOWER */
 			{
 				char	   *p;
 
@@ -1814,7 +1810,6 @@ str_initcap(const char *buff, size_t nbytes, Oid collid)
 		else
 #endif
 		{
-#ifdef USE_WIDE_UPPER_LOWER
 			if (pg_database_encoding_max_length() > 1)
 			{
 				wchar_t    *workspace;
@@ -1865,7 +1860,6 @@ str_initcap(const char *buff, size_t nbytes, Oid collid)
 				pfree(workspace);
 			}
 			else
-#endif							/* USE_WIDE_UPPER_LOWER */
 			{
 				char	   *p;
 
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 3d3d8aa4b6..5ad75efb7a 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -1587,6 +1587,7 @@ icu_from_uchar(char **result, const UChar *buff_uchar, int32_t len_uchar)
 
 	return len_result;
 }
+
 #endif							/* USE_ICU */
 
 /*
@@ -1594,8 +1595,6 @@ icu_from_uchar(char **result, const UChar *buff_uchar, int32_t len_uchar)
  * Therefore we keep them here rather than with the mbutils code.
  */
 
-#ifdef USE_WIDE_UPPER_LOWER
-
 /*
  * wchar2char --- convert wide characters to multibyte format
  *
@@ -1762,5 +1761,3 @@ char2wchar(wchar_t *to, size_t tolen, const char *from, size_t fromlen,
 
 	return result;
 }
-
-#endif							/* USE_WIDE_UPPER_LOWER */
diff --git a/src/include/c.h b/src/include/c.h
index fd53010e24..b6a969787a 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -1095,14 +1095,6 @@ extern int	fdatasync(int fildes);
 #define HAVE_STRTOULL 1
 #endif
 
-/*
- * We assume if we have these two functions, we have their friends too, and
- * can use the wide-character functions.
- */
-#if defined(HAVE_WCSTOMBS) && defined(HAVE_TOWLOWER)
-#define USE_WIDE_UPPER_LOWER
-#endif
-
 /* EXEC_BACKEND defines */
 #ifdef EXEC_BACKEND
 #define NON_EXEC_STATIC
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 85deb29d83..2a4e9f6050 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -593,9 +593,6 @@
    `HAVE_STRUCT_TM_TM_ZONE' instead. */
 #undef HAVE_TM_ZONE
 
-/* Define to 1 if you have the `towlower' function. */
-#undef HAVE_TOWLOWER
-
 /* Define to 1 if your compiler understands `typeof' or something similar. */
 #undef HAVE_TYPEOF
 
@@ -659,9 +656,6 @@
 /* Define to 1 if you have the <wchar.h> header file. */
 #undef HAVE_WCHAR_H
 
-/* Define to 1 if you have the `wcstombs' function. */
-#undef HAVE_WCSTOMBS
-
 /* Define to 1 if you have the `wcstombs_l' function. */
 #undef HAVE_WCSTOMBS_L
 
diff --git a/src/include/pg_config.h.win32 b/src/include/pg_config.h.win32
index 27aab21be7..b6808d581b 100644
--- a/src/include/pg_config.h.win32
+++ b/src/include/pg_config.h.win32
@@ -442,9 +442,6 @@
    `HAVE_STRUCT_TM_TM_ZONE' instead. */
 /* #undef HAVE_TM_ZONE */
 
-/* Define to 1 if you have the `towlower' function. */
-#define HAVE_TOWLOWER 1
-
 /* Define to 1 if your compiler understands `typeof' or something similar. */
 /* #undef HAVE_TYPEOF */
 
@@ -484,9 +481,6 @@
 /* Define to 1 if you have the <wchar.h> header file. */
 #define HAVE_WCHAR_H 1
 
-/* Define to 1 if you have the `wcstombs' function. */
-#define HAVE_WCSTOMBS 1
-
 /* Define to 1 if you have the `wcstombs_l' function. */
 #define HAVE_WCSTOMBS_L 1
 
diff --git a/src/include/tsearch/ts_locale.h b/src/include/tsearch/ts_locale.h
index c32f0743aa..3ec276fc05 100644
--- a/src/include/tsearch/ts_locale.h
+++ b/src/include/tsearch/ts_locale.h
@@ -41,28 +41,16 @@ typedef struct
 
 #define TOUCHAR(x)	(*((const unsigned char *) (x)))
 
-#ifdef USE_WIDE_UPPER_LOWER
+/* The second argument of t_iseq() must be a plain ASCII character */
+#define t_iseq(x,c)		(TOUCHAR(x) == (unsigned char) (c))
+
+#define COPYCHAR(d,s)	memcpy(d, s, pg_mblen(s))
 
 extern int	t_isdigit(const char *ptr);
 extern int	t_isspace(const char *ptr);
 extern int	t_isalpha(const char *ptr);
 extern int	t_isprint(const char *ptr);
 
-/* The second argument of t_iseq() must be a plain ASCII character */
-#define t_iseq(x,c)		(TOUCHAR(x) == (unsigned char) (c))
-
-#define COPYCHAR(d,s)	memcpy(d, s, pg_mblen(s))
-#else							/* not USE_WIDE_UPPER_LOWER */
-
-#define t_isdigit(x)	isdigit(TOUCHAR(x))
-#define t_isspace(x)	isspace(TOUCHAR(x))
-#define t_isalpha(x)	isalpha(TOUCHAR(x))
-#define t_isprint(x)	isprint(TOUCHAR(x))
-#define t_iseq(x,c)		(TOUCHAR(x) == (unsigned char) (c))
-
-#define COPYCHAR(d,s)	(*((unsigned char *) (d)) = TOUCHAR(s))
-#endif							/* USE_WIDE_UPPER_LOWER */
-
 extern char *lowerstr(const char *str);
 extern char *lowerstr_with_len(const char *str, int len);
 
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index f3e04d4d8c..b633511a7a 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -110,11 +110,9 @@ extern int32_t icu_from_uchar(char **result, const UChar *buff_uchar, int32_t le
 #endif
 
 /* These functions convert from/to libc's wchar_t, *not* pg_wchar_t */
-#ifdef USE_WIDE_UPPER_LOWER
 extern size_t wchar2char(char *to, const wchar_t *from, size_t tolen,
 		   pg_locale_t locale);
 extern size_t char2wchar(wchar_t *to, size_t tolen,
 		   const char *from, size_t fromlen, pg_locale_t locale);
-#endif
 
 #endif							/* _PG_LOCALE_ */