git issue #838 - old time manipulation for BSD

Issue #838 from clausecker, relayed by copperwater:  old workarounds
for lack of type 'time_t' from pre-standard days aren't suitable any
more.  One of the instances was incorrect (diagnosed by entrez) and
no one had noticed for years (or possibly just ignored a compiler
warning).

Remove most of the old cruft from hacklib.c and some from system.h
but put in commented workarounds in unixconf.h in case someone needs
to resurrect it.  It would have been better to do things this way
back in the old days.

Resurrecting some non-Unix port might need to clone the unixconf.h
bits in its own *conf.h, but that probably won't be necessary for a
standard C compliant system.

Closes #838

src/hacklib.c

@@ -910,24 +910,15 @@ fuzzymatch(const char *s1, const char *s2, const char *ignore_chars,
  *  - determination of what files are "very old"
  */
 
-/* TIME_type: type of the argument to time(); we actually use &(time_t) */
-#if defined(BSD) && !defined(POSIX_TYPES)
-#define TIME_type long *
-#else
+/* TIME_type: type of the argument to time(); we actually use &(time_t);
+   you might need to define either or both of these to 'long *' in *conf.h */
+#ifndef TIME_type
 #define TIME_type time_t *
 #endif
-/* LOCALTIME_type: type of the argument to localtime() */
-#if (defined(ULTRIX) && !(defined(ULTRIX_PROTO) || defined(NHSTDC))) \
-    || (defined(BSD) && !defined(POSIX_TYPES))
-#define LOCALTIME_type long *
-#else
+#ifndef LOCALTIME_type
 #define LOCALTIME_type time_t *
 #endif
 
-#if defined(AMIGA) && !defined(AZTEC_C) && !defined(__SASC_60) \
-    && !defined(_DCC) && !defined(__GNUC__)
-extern struct tm *localtime(time_t *);
-#endif
 static struct tm *getlt(void);
 
 /* Sets the seed for the random number generator */
@@ -1088,12 +1079,8 @@ yyyymmddhhmmss(time_t date)
     if (date == 0)
         lt = getlt();
     else
-#if (defined(ULTRIX) && !(defined(ULTRIX_PROTO) || defined(NHSTDC))) \
-    || defined(BSD)
-        lt = localtime((long *) (&date));
-#else
-        lt = localtime(&date);
-#endif
+        lt = localtime((LOCALTIME_type) &date);
+
     /* just in case somebody's localtime supplies (year % 100)
        rather than the expected (year - 1900) */
     if (lt->tm_year < 70)