libsparse: add error reporting functions

Change-Id: I2f21355b6c5339d1d724b4c121ea30d575b2d366
diff --git a/libsparse/sparse_file.h b/libsparse/sparse_file.h
index fae1c16..91a12e6 100644
--- a/libsparse/sparse_file.h
+++ b/libsparse/sparse_file.h
@@ -22,6 +22,7 @@
 struct sparse_file {
 	unsigned int block_size;
 	int64_t len;
+	bool verbose;
 
 	struct backed_block_list *backed_block_list;
 	struct output_file *out;