Strip following whitespace in config file lines

tar/bsdtar.c

@@ -1166,18 +1166,22 @@ configfile_helper(struct bsdtar *bsdtar, const char *line)
 	if ((conf_opt = strdup(line)) == NULL)
 		bsdtar_errc(bsdtar, 1, errno, "Out of memory");
 
-	/*
-	 * Detect any trailing whitespace.  This could happen before string
-	 * duplication, but to reduce the number of diffs to a later version,
-	 * we'll do it here.
+	/* Skip any following whitespace.
+	 * We cannot modify 'line' beacuse it is const, so we
+	 * perform this step on the duplicated string.
 	 */
 	len = strlen(conf_opt);
 	if ((len > 0) &&
 	    ((conf_opt[len - 1] == ' ') || (conf_opt[len - 1] == '\t'))) {
 		bsdtar_warnc(bsdtar, 0,
-		    "option contains trailing whitespace; future behaviour"
-		    " may change for:\n    %s", line);
+		    "Automatically stripping trailing whitespace"
+		    " in config file");
+	}
+	while ((len > 0) &&
+	    ((conf_opt[len - 1] == ' ') || (conf_opt[len - 1] == '\t'))) {
+		len--;
 	}
+	conf_opt[len] = '\0';
 
 	/* Split line into option and argument if possible. */
 	optlen = strcspn(conf_opt, " \t");