d.vect generates bogus SQL when 'attrcol' option is given more than once

[dylan]

Example based on today's 6.5-SVN:

d.mon x0
d.vect archsites disp=shape,attr attrcol=str1 attrcol=

Although the user should never construct a command-line such as this, I think that some kind of error checking should be involved. The following SQL is generated:

select str1, from archsites where cat = 1

I see this note in d.vect/main.c:

attrcol_opt = G_define_standard_option(G_OPT_COLUMN);
attrcol_opt->key = "attrcol";
attrcol_opt->multiple = NO;	/* or fix attr.c, around line 102 */
attrcol_opt->guisection = _("Labels");
attrcol_opt->description = _("Name of column to be displayed");

It looks like something is trying to use multiple invocations of the 'attrcol' option to generate a list of columns to be sent to the DB driver.