Don't clear the opt instance in the diff example. The version field is overwritten otherwise. The opt instance is already initialized properly.
diff --git a/examples/diff.c b/examples/diff.c
index 63956aa..17bf842 100644
--- a/examples/diff.c
+++ b/examples/diff.c
@@ -138,8 +138,6 @@ int main(int argc, char *argv[])
int i, color = -1, compact = 0, cached = 0;
char *a, *dir = ".", *treeish1 = NULL, *treeish2 = NULL;
- memset(&opts, 0, sizeof(opts));
-
/* parse arguments as copied from git-diff */
for (i = 1; i < argc; ++i) {