supporting the url form commonly used for the `diffurl`.
You can change your setup to use the newer gitweb url form:
- http://git.example.com/gitweb.cgi?p=wiki.git;a=blobdiff;f=\[[file]];h=\[[sha1\_to]];hp=\[[sha1\_from]];hb=\[[sha1\_commit]];hpb=\[[sha1\_parent]]
+ http://git.example.com/gitweb.cgi?p=wiki.git;a=blobdiff;f=\[[file]];h=\[[sha1_to]];hp=\[[sha1_from]];hb=\[[sha1_commit]];hpb=\[[sha1_parent]]
The changes from the old form are the addition of the `hpb` parameter,
and the change to the value used for the `hb` parameter.