--- a/src/m/sgi-challenge.h	Mon Aug 13 11:19:22 2007 +0200
+++ b/src/m/sgi-challenge.h	Mon Aug 13 11:20:41 2007 +0200
@@ -28,6 +28,11 @@
    operating system this machine is likely to run.
    USUAL-OPSYS="irix3-3"  */
 
+/* Define WORD_MACHINE if addresses and such have
+ * to be corrected before they can be used as byte counts.  */
+
+#undef WORD_MACHINE
+
 /* Now define a symbol for the cpu type, if your compiler
    does not define it automatically:
    Ones defined so far include vax, m68000, ns16000, pyramid,
@@ -49,6 +54,14 @@
 #undef HAVE_NATIVE_SOUND
 #endif
 
+/* Define EXPLICIT_SIGN_EXTEND if XINT must explicitly sign-extend
+   the bit field into an int.  In other words, if bit fields
+   are always unsigned.
+
+   If you use NO_UNION_TYPE, this flag does not matter.  */
+
+#define EXPLICIT_SIGN_EXTEND
+
 /* Data type of load average, as read out of kmem.  */
 
 #define LOAD_AVE_TYPE long	/* This doesn't quite work on the 4D */
@@ -103,7 +116,15 @@
 #define UNEXEC "unexelfsgi.o"
 
 #define TEXT_START 0x400000
+
+/*
+ * DATA_SEG_BITS forces that bit to be or'd in with any pointers which
+ * are trying to access pure strings (as gnu-emacs only allows 24 bits
+ * for the value field of a LISP_OBJECT).
+ */
+
 #define DATA_START 0x10000000
+#define DATA_SEG_BITS	0x10000000
 
 #undef LIBS_MACHINE
 /* -lsun in case using Yellow Pages for passwords.  */