--- bc-2.5.1/include/num.h.orig	Fri Jan 24 19:24:12 2020
+++ bc-2.5.1/include/num.h	Fri Jan 24 19:24:54 2020
@@ -134,6 +134,10 @@
 
 #define BC_NUM_KARATSUBA_ALLOCS (6)
 
+#ifndef SSIZE_MAX
+#define SSIZE_MAX LONG_MAX
+#endif
+
 #define BC_NUM_CMP_SIGNAL_VAL (~((ssize_t) ((size_t) SSIZE_MAX)))
 #define BC_NUM_CMP_SIGNAL(cmp) (cmp == BC_NUM_CMP_SIGNAL_VAL)