Use utsname version on {vax,mips}-dec-ultrix >= 3.0

[Urs Janßen]

Use utsname version instead of preprocessor macros on
{vax,mips}-dec-ultrix >= 3.0
This was tested on mips-dec-ultrix3.1, vax-dec-ultrix3.0 and
vax-dec-ultrix3.1
With the old code vax-dec-ultrix3.0 was detected as vax-dec-ultrix only.

Note: the original ultrix3 /bin/sh don't know shell functions, thus
set_cc_for_build() { ... } caues a syntax error.
"originally" set_cc_for_build was not a function ...

=== modified file 'config.guess'
--- config.guess        2019-03-07 09:11:31 +0000
+++ config.guess        2019-04-25 21:30:40 +0000
@@ -1435,11 +1463,19 @@
 
 # No uname command or uname output not recognized.
 set_cc_for_build
-cat >$dummy.c <<EOF
+cat > "$dummy.c" <<EOF
 #ifdef _SEQUENT_
 #include <sys/types.h>
 #include <sys/utsname.h>
 #endif
+#if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || 
defined(__ultrix__)
+#if defined (vax) || defined (__vax) || defined (__vax__) || defined(mips) || 
defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)
+#include <signal.h>
+#if defined(_SIZE_T_) || defined(SIGLOST)
+#include <sys/utsname.h>
+#endif
+#endif
+#endif
 main ()
 {
 #if defined (sony)
@@ -1527,19 +1563,24 @@
   printf ("vax-dec-bsd\n"); exit (0);
 #endif
 #else
+#if defined(_SIZE_T_) || defined(SIGLOST)
+  struct utsname un;
+  uname(&un);
+  printf ("vax-dec-ultrix%s\n", un.release); exit (0);
+#else
   printf ("vax-dec-ultrix\n"); exit (0);
 #endif
 #endif
+#endif
 #if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || 
defined(__ultrix__)
 #if defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || 
defined(__MIPS__)
-#include <signal.h>
-#if defined(_SIZE_T_) /* >= ULTRIX4 */
-  printf ("mips-dec-ultrix4\n"); exit (0);
+#if defined(_SIZE_T_) || defined(SIGLOST)
+  struct utsname *un;
+  uname(&un);
+  printf ("mips-dec-ultrix%s\n", un.release); exit (0);
 #else
-#if defined(ULTRIX3) || defined(ultrix3) || defined(SIGLOST)
-  printf ("mips-dec-ultrix3\n"); exit (0);
-#endif
-#endif
+  printf ("mips-dec-ultrix\n"); exit (0);
+#endif  
 #endif
 #endif