top: 'X' command offers auto option

The recent introduction of a column widths override
(the 'X' command) provided for a user input amount
to be added to default field size which ranged from
5 to 10 bytes.

While that approach could prevent truncated data, the
different default sizes would almost certainly mean
some precious screen real estate was waisted.

This commit introduces the concept of dynamic widths
where top will add only enough to a field default to
prevent truncation for that specific field.

Now users have a choice between their explicit width
override or a width chosen by top to exactly match
display needs.  The former is immediate but likely
wastes some horizontal space while the latter is
iterative but will be sized precisely.

Original 'X' Command:
commit 384afa494a
commit 47e1d063ac

Extensions to 'X' Command:
commit bbf8e44fb4
commit 7557f3f754

Signed-off-by: Jim Warner <james.warner@comcast.net>

top/top_nls.c

@@ -367,7 +367,7 @@ static void build_norm_nlstab (void) {
    Norm_nlstab[FIND_no_next_txt] = _("Locate next inactive, use \"L\"");
    Norm_nlstab[GET_find_str_txt] = _("Locate string");
    Norm_nlstab[FIND_no_find_fmt] = _("%s\"%s\" not found");
-   Norm_nlstab[XTRA_fixwide_fmt] = _("fixed-width incr is %d, change to (0 = default)");
+   Norm_nlstab[XTRA_fixwide_fmt] = _("width incr is %d, change to (0 default, -1 auto)");
 #ifndef WARN_CFG_OFF
    Norm_nlstab[XTRA_warncfg_txt] = _("Overwrite existing old style rcfile?");
 #endif