--- gcc/config/i386/sco4dbx.h	2018/04/24 18:10:27	1.1.1.1
+++ gcc/config/i386/sco4dbx.h	2018/04/24 18:16:51	1.1.1.2
@@ -60,7 +60,7 @@ the Free Software Foundation, 675 Mass A
    Specify predefined symbols in preprocessor.  */
 
 #undef CPP_PREDEFINES
-#define CPP_PREDEFINES "-Di386 -Dunix"
+#define CPP_PREDEFINES "-Di386 -Dunix -Asystem(unix) -Asystem(svr3) -Acpu(i386) -Amachine(i386)"
 
 #undef CPP_SPEC
 #define CPP_SPEC \