--- gcc/config/tm-i386sco.h	2018/04/24 16:56:42	1.1
+++ gcc/config/tm-i386sco.h	2018/04/24 17:00:06	1.1.1.3
@@ -16,14 +16,24 @@
 
 #undef LIB_SPEC
 #define LIB_SPEC \
- "%{p:-L/usr/lib/libp}%{pg:-L/usr/lib/libp} %{scointl:libintl.a%s} -lc"
+ "%{p:-L/usr/lib/libp}%{pg:-L/usr/lib/libp} libintl.a%s -lc"
 
 /* Specify predefined symbols in preprocessor.  */
 
 #undef CPP_PREDEFINES
 #define CPP_PREDEFINES \
-"-Dunix -Di386 -DM_UNIX -DM_I386 -DM_COFF -DM_WORDSWAP%{scointl: -DM_INTERNAT}"
+"-Dunix -Di386 -DM_UNIX -DM_I386 -DM_COFF -DM_WORDSWAP"
+
+#undef CPP_SPEC
+#define CPP_SPEC "%{posix:-D_POSIX_SOURCE} -DM_INTERNAT"
 
 /* SCO's assember doesn't grok '$' in labels (for g++) */
 
 #define NO_DOLLAR_IN_LABEL
+
+/* SCO's libraries are compiled with Microsoft C, which requires the
+   caller to pop the extra argument passed to functions that return
+   structures. */
+
+#define STRUCT_RETURN_CALLER_POP
+