[gtk-doc] rebase: add tracing support

[Stefan Kost <stefkost src gnome org>]

commit 08e723acccdc0a284c2ac386a8b5c6a0948948eb
Author: Stefan Sauer <ensonic users sf net>
Date:   Sun Jun 5 20:12:55 2016 +0200

    rebase: add tracing support
    
    https://bugzilla.gnome.org/show_bug.cgi?id=767271

 gtkdoc-rebase.in |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/gtkdoc-rebase.in b/gtkdoc-rebase.in
index 127f7a6..30db903 100644
--- a/gtkdoc-rebase.in
+++ b/gtkdoc-rebase.in
@@ -30,6 +30,9 @@ use bytes;
 use Getopt::Long qw(:config gnu_getopt);
 use Cwd qw(realpath);
 
+push @INC, '@PACKAGE_DATA_DIR@';
+require "gtkdoc-common.pl";
+
 # Options
 
 my $HTML_DIR;
@@ -347,6 +350,8 @@ sub RebaseLink {
               $dir = $LocalMap{ $package };
             }
             $href = $dir . $file;
+        } else {
+          @TRACE@("Can't determine package for '$href'");
         }
         if ($dir ne $origdir) {
             if ($Mapped{ $origdir }) {