tar: add support for --overwrite. +70 bytes.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/include/unarchive.h b/include/unarchive.h
index 35ce521..68e83f0 100644
--- a/include/unarchive.h
+++ b/include/unarchive.h
@@ -58,7 +58,7 @@
 	char *ah_buffer;
 
 	/* Flags and misc. stuff */
-	unsigned char ah_flags;
+	unsigned ah_flags;
 
 	/* "Private" storage for archivers */
 //	unsigned char ah_priv_inited;
@@ -74,6 +74,7 @@
 #define ARCHIVE_DONT_RESTORE_OWNER  (1 << 5)
 #define ARCHIVE_DONT_RESTORE_PERM   (1 << 6)
 #define ARCHIVE_NUMERIC_OWNER       (1 << 7)
+#define ARCHIVE_O_TRUNC             (1 << 8)
 
 
 /* Info struct unpackers can fill out to inform users of thing like