diff --git a/doc/fixes3-7-0.txt b/doc/fixes3-7-0.txt
index b084e5a45..7a88b4446 100644
--- a/doc/fixes3-7-0.txt
+++ b/doc/fixes3-7-0.txt
@@ -2092,4 +2092,6 @@ add TT_NONE==0, renumber other u.utraptype values so that TT_BEARTRAP isn't 0
 for Planes of Water and Air, save the air bubbles and clouds with the level
 	rather than as game state; affects wizard mode ^V and #wizmakemap
 switch to a flags arg on newcham() in place of the pair of boolean args
+replace some old 'time_t' hackery in system.h and hacklib.c with something
+	less obtrusive in unixconf.h
 
diff --git a/include/system.h b/include/system.h
index 98bdfdc27..4c126fb10 100644
--- a/include/system.h
+++ b/include/system.h
@@ -534,22 +534,13 @@ E genericptr_t realloc(genericptr_t, size_t);
 
 /* time functions */
 
-#ifndef LATTICE
-#if !(defined(ULTRIX_PROTO) && defined(__GNUC__))
+#ifdef NEED_TIME_DECL
+E time_t time(time_t *);
+#endif
+#ifdef NEED_LOCALTIME_DECL
 E struct tm *localtime(const time_t *);
 #endif
-#endif
-
-#if defined(ULTRIX) || (defined(BSD) && defined(POSIX_TYPES))          \
-    || defined(SYSV) || defined(MICRO) || defined(VMS) || defined(MAC) \
-    || (defined(HPUX) && defined(_POSIX_SOURCE))
-E time_t time(time_t *);
-#else
-E long time(time_t *);
-#endif /* ULTRIX */
-
-#ifdef VMS
-/* used in makedefs.c, but missing from gcc-vms's <time.h> */
+#ifdef NEED_CTIME_DECL
 E char *ctime(const time_t *);
 #endif
 
diff --git a/include/unixconf.h b/include/unixconf.h
index 9a9b77de6..e3e1aee18 100644
--- a/include/unixconf.h
+++ b/include/unixconf.h
@@ -296,6 +296,16 @@
 #include <time.h>
 #endif
 
+/* these might be needed for include/system.h;
+   default comes from system's time.h */
+/* #define NEED_TIME_DECL 1 */
+/* #define NEED_LOCALTIME_DECL 1 */
+/* #define NEED_CTIME_DECL 1 */
+/* these might be needed for src/hacklib.c;
+   default is 'time_t *' */
+/* #define TIME_type long * */
+/* #define LOCALTIME_type long * */
+
 #define HLOCK "perm" /* an empty file used for locking purposes */
 
 #define tgetch getchar
diff --git a/src/hacklib.c b/src/hacklib.c
index 2e644b244..c5e6d9a21 100644
--- a/src/hacklib.c
+++ b/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)