formatting.c cleanup: Change TmFromChar.clock field to bool

This makes the purpose clearer and avoids having two extra symbols,
one of which (CLOCK_24_HOUR) was unused.

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/6dd9d208-a3ed-49b5-b03d-8617261da973%40eisentraut.org

src/backend/utils/adt/formatting.c

@@ -162,9 +162,6 @@ typedef struct
 #define SUFFTYPE_PREFIX		1
 #define SUFFTYPE_POSTFIX	2
 
-#define CLOCK_24_HOUR		0
-#define CLOCK_12_HOUR		1
-
 
 /*
  * Full months
@@ -428,7 +425,7 @@ typedef struct
 	int			j;
 	int			us;
 	int			yysz;			/* is it YY or YYYY ? */
-	int			clock;			/* 12 or 24 hour clock? */
+	bool		clock_12_hour;	/* 12 or 24 hour clock? */
 	int			tzsign;			/* +1, -1, or 0 if no TZH/TZM fields */
 	int			tzh;
 	int			tzm;
@@ -454,7 +451,7 @@ struct fmt_tz					/* do_to_timestamp's timezone info output */
 			(_X)->mode, (_X)->hh, (_X)->pm, (_X)->mi, (_X)->ss, (_X)->ssss, \
 			(_X)->d, (_X)->dd, (_X)->ddd, (_X)->mm, (_X)->ms, (_X)->year, \
 			(_X)->bc, (_X)->ww, (_X)->w, (_X)->cc, (_X)->j, (_X)->us, \
-			(_X)->yysz, (_X)->clock)
+			(_X)->yysz, (_X)->clock_12_hour)
 #define DEBUG_TM(_X) \
 		elog(DEBUG_elog_output, "TM:\nsec %d\nyear %d\nmin %d\nwday %d\nhour %d\nyday %d\nmday %d\nnisdst %d\nmon %d\n",\
 			(_X)->tm_sec, (_X)->tm_year,\
@@ -3225,7 +3222,7 @@ DCH_from_char(FormatNode *node, const char *in, TmFromChar *out,
 					return;
 				if (!from_char_set_int(&out->pm, value % 2, n, escontext))
 					return;
-				out->clock = CLOCK_12_HOUR;
+				out->clock_12_hour = true;
 				break;
 			case DCH_AM:
 			case DCH_PM:
@@ -3237,13 +3234,13 @@ DCH_from_char(FormatNode *node, const char *in, TmFromChar *out,
 					return;
 				if (!from_char_set_int(&out->pm, value % 2, n, escontext))
 					return;
-				out->clock = CLOCK_12_HOUR;
+				out->clock_12_hour = true;
 				break;
 			case DCH_HH:
 			case DCH_HH12:
 				if (from_char_parse_int_len(&out->hh, &s, 2, n, escontext) < 0)
 					return;
-				out->clock = CLOCK_12_HOUR;
+				out->clock_12_hour = true;
 				SKIP_THth(s, n->suffix);
 				break;
 			case DCH_HH24:
@@ -4456,7 +4453,7 @@ do_to_timestamp(const text *date_txt, const text *fmt, Oid collid, bool std,
 	if (tmfc.hh)
 		tm->tm_hour = tmfc.hh;
 
-	if (tmfc.clock == CLOCK_12_HOUR)
+	if (tmfc.clock_12_hour)
 	{
 		if (tm->tm_hour < 1 || tm->tm_hour > HOURS_PER_DAY / 2)
 		{