Point out more explicitly that 'tz' argument should normally be NULL.

Various other minor edits and formatting fixes.

man2/gettimeofday.2

@@ -60,14 +60,14 @@ argument is a
 (as specified  in 
 .IR <sys/time.h> ):
 .sp
+.in +0.25i
 .nf
 struct timeval {
-.in +8
-time_t		tv_sec;		/* seconds */
-suseconds_t	tv_usec;	/* microseconds */
-.in -8
+    time_t      tv_sec;     /* seconds */
+    suseconds_t tv_usec;    /* microseconds */
 };
 .fi
+.in -0.25i
 .sp
 and gives the number of seconds and microseconds since the Epoch (see
 .BR time (2)).
@@ -76,16 +76,31 @@ The
 argument is a 
 .IR "struct timezone" :
 .sp
+.in +0.25i
 .nf
 struct timezone {
-.in +8
-int	tz_minuteswest; /* minutes W of Greenwich */
-int	tz_dsttime;     /* type of dst correction */
-.in -8
+    int tz_minuteswest;     /* minutes W of Greenwich */
+    int tz_dsttime;         /* type of dst correction */
 };
 .fi
+.in -0.25i
 .PP
-The use of the timezone struct is obsolete: the
+If either
+.I tv
+or 
+.I tz
+is NULL, the corresponding structure is not set or returned.
+.\" The following is covered under EPERM below:
+.\" .PP
+.\" Only the superuser may use
+.\" .BR settimeofday ().
+.PP
+The use of the 
+.I timezone 
+structure is obsolete; the
+.I tz
+argument should normally be specfied as NULL.
+The
 .I tz_dsttime
 field has never been used under Linux; it has not
 been and will not be supported by libc or glibc.
@@ -102,28 +117,27 @@ it does not indicate that DST is in force, it just selects an
 algorithm.)
 The daylight saving time algorithms defined are as follows : 
 .PP
-.ta 14
-\fB DST_NONE\fP	/* not on dst */
+\fB DST_NONE\fP    /* not on dst */
 .br
-\fB DST_USA\fP	/* USA style dst */
+\fB DST_USA\fP     /* USA style dst */
 .br
-\fB DST_AUST\fP	/* Australian style dst */
+\fB DST_AUST\fP    /* Australian style dst */
 .br
-\fB DST_WET\fP	/* Western European dst */
+\fB DST_WET\fP     /* Western European dst */
 .br
-\fB DST_MET\fP	/* Middle European dst */
+\fB DST_MET\fP     /* Middle European dst */
 .br
-\fB DST_EET\fP	/* Eastern European dst */
+\fB DST_EET\fP     /* Eastern European dst */
 .br
-\fB DST_CAN\fP	/* Canada */
+\fB DST_CAN\fP     /* Canada */
 .br
-\fB DST_GB\fP	/* Great Britain and Eire */
+\fB DST_GB\fP      /* Great Britain and Eire */
 .br
-\fB DST_RUM\fP	/* Rumania */
+\fB DST_RUM\fP     /* Rumania */
 .br
-\fB DST_TUR\fP	/* Turkey */
+\fB DST_TUR\fP     /* Turkey */
 .br
-\fB DST_AUSTALT\fP	/* Australian style with shift in 1986 */
+\fB DST_AUSTALT\fP /* Australian style with shift in 1986 */
 .PP
 Of course it turned out that the period in which
 Daylight Saving Time is in force cannot be given
@@ -155,28 +169,19 @@ The following macros are defined to operate on a
 .IR "struct timeval" :
 .sp
 .nf
-#define	timerisset(tvp)\\
+#define timerisset(tvp)\\
 .ti +8
 ((tvp)\->tv_sec || (tvp)\->tv_usec)
-#define	timercmp(tvp, uvp, cmp)\\
+#define timercmp(tvp, uvp, cmp)\\
 .in +8
 ((tvp)\->tv_sec cmp (uvp)\->tv_sec ||\\
 (tvp)\->tv_sec == (uvp)\->tv_sec &&\\
 (tvp)\->tv_usec cmp (uvp)\->tv_usec)
 .in -8
-#define	timerclear(tvp)\\
+#define timerclear(tvp)\\
 .ti +8
 ((tvp)\->tv_sec = (tvp)\->tv_usec = 0)
 .fi
-.PP
-If either
-.I tv
-or 
-.I tz
-is null, the corresponding structure is not set or returned.
-.PP
-Only the superuser may use
-.BR settimeofday ().
 .SH "RETURN VALUE"
 .BR gettimeofday ()
 and