This trivial patch fixes an obvious ptrdiff_t vs. int mismatch.

Signed-off-by: Markus F.X.J. Oberhumer <markus@oberhumer.com>

Index: diff-tree.c
===================================================================
--- 1348af9952a1d26b2ad14ec8f433322fd79510f3/diff-tree.c  (mode:100644)
+++ 61dcf68d605a8d9204c24278dbdc73b4cf7ccc90/diff-tree.c  (mode:100644)
@@ -274,7 +274,7 @@
 			for (cp = header; *cp; cp = ep) {
 				ep = strchr(cp, '\n');
 				if (ep == 0) ep = cp + strlen(cp);
-				printf("%.*s%c", ep-cp, cp, 0);
+				printf("%.*s%c", (int) (ep-cp), cp, 0);
 				if (*ep) ep++;
 			}
 		}