(CPP_SPEC): Add '-trigraphs' because IBM's h files contain them.

From-SVN: r11257

gcc/config/i370/i370.h

 /* Definitions of target machine for GNU compiler.  System/370 version.
-   Copyright (C) 1989, 1993, 1995 Free Software Foundation, Inc.
+   Copyright (C) 1989, 1993, 1995, 1996 Free Software Foundation, Inc.
    Contributed by Jan Stein (jan@cd.chalmers.se).
    Modified for C/370 MVS by Dave Pitts (dpitts@nyx.cs.du.edu)
 
@@ -28,6 +28,10 @@ Boston, MA 02111-1307, USA.  */
 
 #define TARGET_VERSION printf (" (370/MVS)");
 
+/* Options for the preprocessor for this target machine.  */
+
+#define CPP_SPEC "-trigraphs"
+
 /* Names to predefine in the preprocessor for this target machine.  */
 
 #define CPP_PREDEFINES "-DGCC -Dgcc -DMVS -Dmvs -Asystem(mvs) -Acpu(i370) -Amachine(i370)"