Assume wcstombs(), towlower(), and sibling functions are always present.

These functions are required by SUS v2, which is our minimum baseline
for Unix platforms, and are present on all interesting Windows versions
as well.  Even our oldest buildfarm members have them.  Thus, we were not
testing the "!USE_WIDE_UPPER_LOWER" code paths, which explains why the bug
fixed in commit e6023ee7f escaped detection.  Per discussion, there seems
to be no more real-world value in maintaining this option.  Hence, remove
the configure-time tests for wcstombs() and towlower(), remove the
USE_WIDE_UPPER_LOWER symbol, and remove all the !USE_WIDE_UPPER_LOWER code.
There's not actually all that much of the latter, but simplifying the #if
nests is a win in itself.

Discussion: https://postgr.es/m/20170921052928.GA188913@rfd.leadboat.com

13 files changed, 18 insertions, 139 deletions

diff --git a/configure b/configure
index 5c38149a3df..70d8aa649d5 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 176b29a7920..cdf11bf6734 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 6982879688b..b2122e9e8fa 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 2b89f596f08..4a799f25859 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 1aa3e237338..7a6f0bc7221 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 e841a1ccf0e..c118357336d 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 2bf484cda31..7877af2d6be 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 3d3d8aa4b65..5ad75efb7a2 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 fd53010e249..b6a969787ac 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 85deb29d831..2a4e9f60500 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 27aab21be77..b6808d581b9 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 c32f0743aa6..3ec276fc05d 100644
--- a/src/include/tsearch/ts_locale.h
+++ b/src/include/tsearch/ts_locale.h
@@ -41,27 +41,15 @@ typedef struct
 
 #define TOUCHAR(x)	(*((const unsigned char *) (x)))
 
-#ifdef USE_WIDE_UPPER_LOWER
-
-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 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);
 
 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 f3e04d4d8ce..b633511a7a5 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_ */