diff --git a/Makefile b/Makefile
index 8aed3af016..3ecd674c14 100644
--- a/Makefile
+++ b/Makefile
@@ -199,7 +199,7 @@ LIB_H = \
 	tree-walk.h log-tree.h
 
 DIFF_OBJS = \
-	diff.o diffcore-break.o diffcore-order.o \
+	diff-lib.o diffcore-break.o diffcore-order.o \
 	diffcore-pickaxe.o diffcore-rename.o tree-diff.o combine-diff.o \
 	diffcore-delta.o log-tree.o
 
diff --git a/diff.c b/diff-lib.c
similarity index 100%
rename from diff.c
rename to diff-lib.c