🚀 go-pugleaf

GNU diff 1.12 sometimes outputs an extra character at the start of a line
when given the -t flag.  Here is a sample transcript:

	rise% cat a
	X
	Y
	X
	rise% cat b
	X
	rise% diff -t a b
	2,3d1
	< Y
	X< X

Here is a fix:

*** old/util.c	Fri Nov 17 16:10:28 1989
--- new/util.c	Fri Nov 17 16:01:52 1989
***************
*** 400,406 ****
	  {
		register int column = 0;
		register int i;
!       for (i = 0; i <= line->length; i++)
	{
	  register char c = line->text[i];
	  if (c == '\t')
--- 400,406 ----
	  {
		register int column = 0;
		register int i;
!       for (i = 0; i < line->length; i++)
	{
	  register char c = line->text[i];
	  if (c == '\t')