Rename typedef "string" to "VarString".

Since pgindent treats typedef names as global, the original coding of
b47b4db would have had rather nasty effects on the formatting
of other files in which "string" is used as a variable or field name.
Use a less generic name for this typedef, and rename some other
identifiers to match.

Peter Geoghegan, per gripe from me

Author: tglsfdc

src/backend/utils/adt/varlena.c

@@ -40,7 +40,7 @@
 int			bytea_output = BYTEA_OUTPUT_HEX;
 
 typedef struct varlena unknown;
-typedef struct varlena string;
+typedef struct varlena VarString;
 
 typedef struct
 {
@@ -75,7 +75,7 @@ typedef struct
 #ifdef HAVE_LOCALE_T
 	pg_locale_t locale;
 #endif
-} StringSortSupport;
+} VarStringSortSupport;
 
 /*
  * This should be large enough that most strings will fit, but small enough
@@ -89,8 +89,8 @@ typedef struct
 #define PG_GETARG_UNKNOWN_P_COPY(n) DatumGetUnknownPCopy(PG_GETARG_DATUM(n))
 #define PG_RETURN_UNKNOWN_P(x)		PG_RETURN_POINTER(x)
 
-#define DatumGetStringP(X)			((string *) PG_DETOAST_DATUM(X))
-#define DatumGetStringPP(X)			((string *) PG_DETOAST_DATUM_PACKED(X))
+#define DatumGetVarStringP(X)		((VarString *) PG_DETOAST_DATUM(X))
+#define DatumGetVarStringPP(X)		((VarString *) PG_DETOAST_DATUM_PACKED(X))
 
 static int	varstrfastcmp_c(Datum x, Datum y, SortSupport ssup);
 static int bpcharfastcmp_c(Datum x, Datum y, SortSupport ssup);
@@ -1766,7 +1766,7 @@ varstr_sortsupport(SortSupport ssup, Oid collid, bool bpchar)
 {
 	bool		abbreviate = ssup->abbreviate;
 	bool		collate_c = false;
-	StringSortSupport *sss;
+	VarStringSortSupport *sss;
 
 #ifdef HAVE_LOCALE_T
 	pg_locale_t locale = 0;
@@ -1853,7 +1853,7 @@ varstr_sortsupport(SortSupport ssup, Oid collid, bool bpchar)
 	 */
 	if (abbreviate || !collate_c)
 	{
-		sss = palloc(sizeof(StringSortSupport));
+		sss = palloc(sizeof(VarStringSortSupport));
 		sss->buf1 = palloc(TEXTBUFLEN);
 		sss->buflen1 = TEXTBUFLEN;
 		sss->buf2 = palloc(TEXTBUFLEN);
@@ -1909,8 +1909,8 @@ varstr_sortsupport(SortSupport ssup, Oid collid, bool bpchar)
 static int
 varstrfastcmp_c(Datum x, Datum y, SortSupport ssup)
 {
-	string	   *arg1 = DatumGetStringPP(x);
-	string	   *arg2 = DatumGetStringPP(y);
+	VarString  *arg1 = DatumGetVarStringPP(x);
+	VarString  *arg2 = DatumGetVarStringPP(y);
 	char	   *a1p,
 			   *a2p;
 	int			len1,
@@ -1979,10 +1979,10 @@ bpcharfastcmp_c(Datum x, Datum y, SortSupport ssup)
 static int
 varstrfastcmp_locale(Datum x, Datum y, SortSupport ssup)
 {
-	string	   *arg1 = DatumGetStringPP(x);
-	string	   *arg2 = DatumGetStringPP(y);
-	bool		arg1_match;
-	StringSortSupport *sss = (StringSortSupport *) ssup->ssup_extra;
+	VarString	   *arg1 = DatumGetVarStringPP(x);
+	VarString	   *arg2 = DatumGetVarStringPP(y);
+	bool			arg1_match;
+	VarStringSortSupport *sss = (VarStringSortSupport *) ssup->ssup_extra;
 
 	/* working state */
 	char	   *a1p,
@@ -2134,9 +2134,9 @@ varstrcmp_abbrev(Datum x, Datum y, SortSupport ssup)
 static Datum
 varstr_abbrev_convert(Datum original, SortSupport ssup)
 {
-	StringSortSupport *sss = (StringSortSupport *) ssup->ssup_extra;
-	string	   *authoritative = DatumGetStringPP(original);
-	char	   *authoritative_data = VARDATA_ANY(authoritative);
+	VarStringSortSupport *sss = (VarStringSortSupport *) ssup->ssup_extra;
+	VarString	   *authoritative = DatumGetVarStringPP(original);
+	char		   *authoritative_data = VARDATA_ANY(authoritative);
 
 	/* working state */
 	Datum		res;
@@ -2311,7 +2311,7 @@ varstr_abbrev_convert(Datum original, SortSupport ssup)
 static bool
 varstr_abbrev_abort(int memtupcount, SortSupport ssup)
 {
-	StringSortSupport *sss = (StringSortSupport *) ssup->ssup_extra;
+	VarStringSortSupport *sss = (VarStringSortSupport *) ssup->ssup_extra;
 	double		abbrev_distinct,
 				key_distinct;