--- gcc/config/i386sco.h	2018/04/24 17:51:38	1.1
+++ gcc/config/i386sco.h	2018/04/24 18:06:12	1.1.1.4
@@ -5,12 +5,24 @@
 
 #include "i386v.h"
 
+/* By default, target has a 80387, uses IEEE compatible arithmetic,
+   and returns float values in the 387, ie,
+   (TARGET_80387 | TARGET_FLOAT_RETURNS_IN_80387)
+
+   SCO's software emulation of a 387 fails to handle the `fucomp'
+   opcode.  fucomp is only used when generating IEEE compliant code.
+   So don't make TARGET_IEEE_FP default for SCO. */
+
+#undef TARGET_DEFAULT
+#define TARGET_DEFAULT 0201
+
 /* Use crt1.o as a startup file and crtn.o as a closing file.  */
 
 #undef STARTFILE_SPEC
-#define STARTFILE_SPEC  "%{pg:gcrt1.o%s}%{!pg:%{p:mcrt1.o%s}%{!p:crt1.o%s}}"
+#define STARTFILE_SPEC \
+ "%{pg:gcrt1.o%s}%{!pg:%{p:mcrt1.o%s}%{!p:crt1.o%s}} crtbegin.o%s"
 
-#define ENDFILE_SPEC "crtn.o%s"
+#define ENDFILE_SPEC "crtend.o%s crtn.o%s"
 
 /* Library spec, including SCO international language support. */
 
@@ -23,8 +35,27 @@
 #undef CPP_PREDEFINES
 #define CPP_PREDEFINES "-Dunix -Di386 -DM_UNIX -DM_I386 -DM_COFF -DM_WORDSWAP"
 
+#undef CPP_SPEC
 #define CPP_SPEC "%{scointl:-DM_INTERNAT}"
 
+/* This spec is used for telling cpp whether char is signed or not.  */
+
+#undef SIGNED_CHAR_SPEC
+#if DEFAULT_SIGNED_CHAR
+#define SIGNED_CHAR_SPEC \
+ "%{funsigned-char:-D__CHAR_UNSIGNED__ -D_CHAR_UNSIGNED}"
+#else
+#define SIGNED_CHAR_SPEC \
+ "%{!fsigned-char:-D__CHAR_UNSIGNED__ -D_CHAR_UNSIGNED}"
+#endif
+
+/* Use atexit for static destructors, instead of defining
+   our own exit function.  */
+#define HAVE_ATEXIT
+
+/* Specify the size_t type.  */
+#define SIZE_TYPE "unsigned int"
+
 #if 0 /* Not yet certain whether this is needed.  */
 /* If no 387, use the general regs to return floating values,
    since this system does not emulate the 80387.  */
@@ -42,3 +73,17 @@
 		     && GET_MODE_UNIT_SIZE (MODE) <= 8)			\
    : (MODE) != QImode)
 #endif
+
+/* caller has to pop the extra argument passed to functions that return
+   structures. */
+
+#undef RETURN_POPS_ARGS
+#define RETURN_POPS_ARGS(FUNTYPE,SIZE)   \
+  (TREE_CODE (FUNTYPE) == IDENTIFIER_NODE ? 0			\
+   : (TARGET_RTD						\
+      && (TYPE_ARG_TYPES (FUNTYPE) == 0				\
+	  || (TREE_VALUE (tree_last (TYPE_ARG_TYPES (FUNTYPE)))	\
+	      == void_type_node))) ? (SIZE)			\
+   : 0)
+/* On other 386 systems, the last line looks like this:
+   : (aggregate_value_p (FUNTYPE)) ? GET_MODE_SIZE (Pmode) : 0)  */