prefix_filename(): safely handle the case where pfx_len=0

diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index 1ebab687f77218d1520a4527214170eeab176d31..da67c04357dfe4d3283c589f5d47be9c5f2b7fcf 100644 (file)
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -26,7 +26,7 @@
 
 #define XDL_MAX_COST_MIN 256
 #define XDL_HEUR_MIN_COST 256
-#define XDL_LINE_MAX (long)((1UL << (8 * sizeof(long) - 1)) - 1)
+#define XDL_LINE_MAX (long)((1UL << (CHAR_BIT * sizeof(long) - 1)) - 1)
 #define XDL_SNAKE_CNT 20
 #define XDL_K_HEUR 4