--- gcc/config/xm-i386sco.h	2018/04/24 17:55:21	1.1.1.1
+++ gcc/config/xm-i386sco.h	2018/04/24 18:06:20	1.1.1.3
@@ -5,3 +5,15 @@
 /* On SCO 3.2.1, ldexp rejects values outside [0.5, 1). */
 
 #define BROKEN_LDEXP
+
+/* Big buffers improve performance.  */
+
+#define IO_BUFFER_SIZE (0x8000 - 1024)
+
+#ifndef __GNUC__
+/* The SCO compiler gets it wrong, and treats enumerated bitfields
+   as signed quantities, making it impossible to use an 8-bit enum
+   for compiling GNU C++.  */
+#define ONLY_INT_FIELDS 1
+#define CODE_FIELD_BUG 1
+#endif