--no-ext-diff::
Disallow external diff drivers.
---ignore-submodules::
- Ignore changes to submodules in the diff generation.
+--ignore-submodules[=<when>]::
+ Ignore changes to submodules in the diff generation. <when> can be
+ either "untracked", "dirty" or "all", which is the default. When
+ "untracked" is used submodules are not considered dirty when they only
+ contain untracked content (but they are still scanned for modified
+ content). Using "dirty" ignores all changes to the work tree of submodules,
+ only changes to the commits stored in the superproject are shown (this was
+ the behavior until 1.7.0). Using "all" hides all changes to submodules.
--src-prefix=<prefix>::
Show the given source prefix instead of "a/".