* date.c, localtime.c, zdump.c: Simplify prototypes for static functions

by removing prototypes that aren't needed, and by removing names
of arguments.  This will make future changes simpler and easier to
follow.
* NEWS: Document this.

NEWS

@@ -47,6 +47,8 @@ Unreleased, experimental changes
     the date it updates the wtmpx file if _PATH_WTMPX is defined.
     This affects GNU/Linux and similar systems.
 
+    Some C code has been simplified for easier maintenance later.
+
   Changes affecting distribution tarballs
 
     The files checktab.awk and zoneinfo2tdf.pl are now distributed in

date.c

@@ -60,11 +60,9 @@ static void		display(const char *, time_t);
 static void		dogmt(void);
 static void		errensure(void);
 static void		iffy(time_t, time_t, const char *, const char *);
-int			main(int, char**);
 static const char *	nondigit(const char *);
 static void		oops(const char *);
 static void		reset(time_t, int);
-static int		sametm(const struct tm *, const struct tm *);
 static void		timeout(FILE *, const char *, const struct tm *);
 static void		usage(void);
 static void		wildinput(const char *, const char *,

localtime.c

@@ -126,59 +126,14 @@ struct rule {
 #define DAY_OF_YEAR		1	/* n = day of year */
 #define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d = month, week, day of week */
 
-/*
-** Prototypes for static functions.
-*/
-
-static int_fast32_t	detzcode(const char * codep);
-static int_fast64_t	detzcode64(const char * codep);
-static int		differ_by_repeat(time_t t1, time_t t0);
-static const char *	getzname(const char * strp) ATTRIBUTE_PURE;
-static const char *	getqzname(const char * strp, const int delim)
-  ATTRIBUTE_PURE;
-static const char *	getnum(const char * strp, int * nump, int min,
-				int max);
-static const char *	getsecs(const char * strp, int_fast32_t * secsp);
-static const char *	getoffset(const char * strp, int_fast32_t * offsetp);
-static const char *	getrule(const char * strp, struct rule * rulep);
-static void		gmtload(struct state * sp);
-static struct tm *	gmtsub(const time_t * timep, int_fast32_t offset,
-				struct tm * tmp);
-static struct tm *	localsub(const time_t * timep, int_fast32_t offset,
-				struct tm * tmp);
-static int		increment_overflow(int * number, int delta);
-static int		leaps_thru_end_of(int y) ATTRIBUTE_PURE;
-static int		increment_overflow32(int_fast32_t * number, int delta);
-static int		increment_overflow_time(time_t *t, int_fast32_t delta);
-static int		normalize_overflow32(int_fast32_t * tensptr,
-				int * unitsptr, int base);
-static int		normalize_overflow(int * tensptr, int * unitsptr,
-				int base);
-static void		settzname(void);
-static time_t		time1(struct tm * tmp,
-				struct tm * (*funcp)(const time_t *,
-				int_fast32_t, struct tm *),
-				int_fast32_t offset);
-static time_t		time2(struct tm *tmp,
-				struct tm * (*funcp)(const time_t *,
-				int_fast32_t, struct tm*),
-				int_fast32_t offset, int * okayp);
-static time_t		time2sub(struct tm *tmp,
-				struct tm * (*funcp)(const time_t *,
-				int_fast32_t, struct tm*),
-				int_fast32_t offset, int * okayp, int do_norm_secs);
-static struct tm *	timesub(const time_t * timep, int_fast32_t offset,
-				const struct state * sp, struct tm * tmp);
-static int		tmcomp(const struct tm * atmp,
-				const struct tm * btmp);
-static int_fast32_t	transtime(int year, const struct rule * rulep,
-				  int_fast32_t offset)
-  ATTRIBUTE_PURE;
-static int		typesequiv(const struct state * sp, int a, int b);
-static int		tzload(const char * name, struct state * sp,
-				int doextend);
-static int		tzparse(const char * name, struct state * sp,
-				int lastditch);
+static struct tm *gmtsub(time_t const *, int_fast32_t, struct tm *);
+static int increment_overflow(int *, int);
+static int increment_overflow_time(time_t *, int_fast32_t);
+static int normalize_overflow32(int_fast32_t *, int *, int);
+static struct tm *timesub(time_t const *, int_fast32_t, struct state const *,
+			  struct tm *);
+static int typesequiv(struct state const *, int, int);
+static int tzparse(char const *, struct state *, int);
 
 #ifdef ALL_STATE
 static struct state *	lclptr;
@@ -657,7 +612,7 @@ static const int	year_lengths[2] = {
 ** character.
 */
 
-static const char *
+static const char * ATTRIBUTE_PURE
 getzname(register const char *strp)
 {
 	register char	c;
@@ -677,7 +632,7 @@ getzname(register const char *strp)
 ** We don't do any checking here; checking is done later in common-case code.
 */
 
-static const char *
+static const char * ATTRIBUTE_PURE
 getqzname(register const char *strp, const int delim)
 {
 	register int	c;
@@ -839,7 +794,7 @@ getrule(const char *strp, register struct rule *const rulep)
 ** effect, calculate the year-relative time that rule takes effect.
 */
 
-static int_fast32_t
+static int_fast32_t ATTRIBUTE_PURE
 transtime(const int year, register const struct rule *const rulep,
 	  const int_fast32_t offset)
 {
@@ -1419,7 +1374,7 @@ offtime(const time_t *const timep, const long offset)
 ** where, to make the math easy, the answer for year zero is defined as zero.
 */
 
-static int
+static int ATTRIBUTE_PURE
 leaps_thru_end_of(register const int y)
 {
 	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :

zdump.c

@@ -207,14 +207,13 @@ static size_t	longest;
 static char *	progname;
 static int	warned;
 
-static char *	abbr(struct tm * tmp);
-static void	abbrok(const char * abbrp, const char * zone);
-static intmax_t	delta(struct tm * newp, struct tm * oldp) ATTRIBUTE_PURE;
-static void	dumptime(const struct tm * tmp);
-static time_t	hunt(char * name, time_t lot, time_t	hit);
-static void	show(char * zone, time_t t, int v);
-static const char *	tformat(void);
-static time_t	yeartot(intmax_t y) ATTRIBUTE_PURE;
+static char *abbr(struct tm *);
+static intmax_t	delta(struct tm *, struct tm *) ATTRIBUTE_PURE;
+static void dumptime(struct tm const *);
+static time_t hunt(char *, time_t, time_t);
+static void show(char *, time_t, int);
+static const char *tformat(void);
+static time_t yeartot(intmax_t) ATTRIBUTE_PURE;
 
 /* Is A an alphabetic character in the C locale?  */
 static int