[PATCH] boxplot: distinguish prefix factors

[Jouke W. <j.w...@gm...>]

When a factor name is a prefix of another, gnuplot treats them as the same.
Hence a datafile with
0	0	0	foobar
0	1	0	foo
will lead to only one boxplot.

This patch fixes that issue.
---
diff -Naur gnuplot-5.0.0.orig/src/plot2d.c gnuplot-5.0.0/src/plot2d.c
--- gnuplot-5.0.0.orig/src/plot2d.c	2015-01-02 21:57:32.551558965 +0100
+++ gnuplot-5.0.0/src/plot2d.c	2015-01-02 21:58:13.929255645 +0100
@@ -1520,7 +1520,7 @@
     len = strlen(trimmed_string);
     for (label = plot->labels; label; label = label->next) {
 	/* check if string is the same as the i-th factor */
-	if (label->text && !strncmp(trimmed_string, label->text, len))
+	if (label->text && !strncmp(trimmed_string, label->text, len + 1))
 		break;
     }