mklog: Fix extraction of changed file name.

2017-07-17  Yury Gribov  <tetra2005@gmail.com>

	* mklog: Fix extraction of changed file name.

From-SVN: r250314

contrib/ChangeLog

+2017-07-17  Yury Gribov  <tetra2005@gmail.com>
+
+	* mklog: Fix extraction of changed file name.
+
 2017-07-17  Georg-Johann Lay  <avr@gjlay.de>
 
 	* gcc_update (files_and_dependencies)

contrib/mklog

 #!/usr/bin/perl
-# Copyright (C) 2012-2014 Free Software Foundation, Inc.
+# Copyright (C) 2012-2017 Free Software Foundation, Inc.
 #
 # This file is part of GCC.
 #
@@ -195,8 +195,20 @@ foreach (@diff_lines) {
 	} elsif($right eq '/dev/null') {
 		$filename = $left;
 	} else {
-		print STDERR "Error: failed to parse diff for $left and $right\n";
-		exit 1;
+		my @ldirs = split /[\/\\]/, $left;
+		my @rdirs = split /[\/\\]/, $right;
+
+		$filename = '';
+		while ((my $l = pop @ldirs) && (my $r = pop @rdirs)) {
+			last if ($l ne $r);
+			$filename = "$l/$filename";
+		}
+		$filename =~ s/\/$//;
+
+		if (!$filename) {
+			print STDERR "Error: failed to parse diff for $left and $right\n";
+			exit 1;
+		}
 	}
 	$left = $right = undef;
 	($clname, $relname) = get_clname ($filename);