seq: Fix equal width calculation when '.' added to last number

Issue reported by Samuel Hapák.
<http://lists.gnu.org/archive/html/bug-coreutils/2009-02/msg00139.html>

* src/seq.c: Account for '.' added to "last" number.
* tests/misc/seq: Add corresponding test.
* NEWS: Mention the fix.

NEWS

@@ -35,6 +35,9 @@ GNU coreutils NEWS                                    -*- outline -*-
   Even with this patch, on some systems, it still produces invalid output,
   from 3 to at least 1026 lines long. [bug introduced in coreutils-6.11]
 
+  seq -w now accounts for a decimal point added to the last number
+  to correctly print all numbers to the same width.
+
   wc --files0-from=FILE no longer reads all of FILE into RAM, before
   processing the first file name, unless the list of names is known
   to be small enough.

src/seq.c

@@ -317,6 +317,8 @@ get_default_format (operand first, operand step, operand last)
 	  size_t last_width = last.width + (prec - last.precision);
 	  if (last.precision && prec == 0)
 	    last_width--;  /* don't include space for '.' */
+	  if (last.precision == 0 && prec)
+	    last_width++;  /* include space for '.' */
 	  size_t width = MAX (first_width, last_width);
 	  if (width <= INT_MAX)
 	    {

tests/misc/seq

@@ -64,6 +64,7 @@ my @Tests =
    ['eq-wid-5',	qw(-w 1 .5 2),  {OUT => [qw(1.0 1.5 2.0)]}],
    ['eq-wid-6',	qw(-w +1 2),  {OUT => [qw(1 2)]}],
    ['eq-wid-7',	qw(-w "    .1"  "    .1"),  {OUT => [qw(0.1)]}],
+   ['eq-wid-8',	qw(-w 9 0.5 10),  {OUT => [qw(09.0 09.5 10.0)]}],
 
    # Prior to coreutils-4.5.11, some of these were not accepted.
    ['fmt-1',	qw(-f %2.1f 1.5 .5 2),{OUT => [qw(1.5 2.0)]}],