Avoid interger overflow when calculating remaining line length

When the len and cidx were changed to size_t in a8a1b093, it was
possible to have an integer overflow when a line ended right at the
edge of the terminal width.

Signed-off-by: Allan McRae <allan@archlinux.org>

src/pacman/util.c

@@ -304,7 +304,7 @@ void indentprint(const char *str, unsigned short indent, unsigned short cols)
 			while(q < next) {
 				len += wcwidth(*q++);
 			}
-			if(len > (cols - cidx - 1)) {
+			if((len + 1) > (cols - cidx)) {
 				/* wrap to a newline and reindent */
 				printf("\n%-*s", (int)indent, "");
 				cidx = indent;