Bug 345405: showdependencygraph.cgi: Dependency Graphs are broken on mod_perl

Bugzilla/Constants.pm

@@ -433,7 +433,7 @@ sub bz_locations {
         # change showdependencygraph.cgi to set image_url to the correct 
         # location.
         # The script should really generate these graphs directly...
-        'webdotdir'   => "$datadir/webdot",
+        'webdotdir'   => "$libpath/$datadir/webdot",
         'extensionsdir' => "$libpath/extensions",
     };
 }

showdependencygraph.cgi

@@ -248,6 +248,11 @@ if ($webdotbase =~ /^https?:/) {
     # On Windows $pngfilename will contain \ instead of /
     $pngfilename =~ s|\\|/|g if $^O eq 'MSWin32';
 
+    # Under mod_perl, pngfilename will have an absolute path, and we
+    # need to make that into a relative path.
+    my $cgi_root = bz_locations()->{cgi_path};
+    $pngfilename =~ s/^\Q$cgi_root\E//;
+    
     $vars->{'image_url'} = $pngfilename;
 
     # Then, generate a imagemap datafile that contains the corner data