diff --git a/lib/cmpbuf.c b/lib/cmpbuf.c
index 369c985..48b9836 100644
--- a/lib/cmpbuf.c
+++ b/lib/cmpbuf.c
@@ -30,10 +30,6 @@
 
 #include "minmax.h"
 
-#ifndef SSIZE_MAX
-# define SSIZE_MAX TYPE_MAXIMUM (ssize_t)
-#endif
-
 /* Read NBYTES bytes from descriptor FD into BUF.
    Return the number of characters successfully read.
    On error, return -1, setting errno.