sim: ppc: drop unused /dev/zero logic

Nothing in the tree checks this option, or has checked for decades.
The pre-cvs-import ChangeLog suggests this was added & removed back
then, but can't be sure as that history doesn't exist in the VCS.

sim/ppc/Makefile.in

@@ -74,7 +74,6 @@ FLOAT_CFLAGS = @sim_float@
 MONITOR_CFLAGS = @sim_monitor@
 MODEL_CFLAGS = @sim_model@ @sim_default_model@ @sim_model_issue@
 TERMIO_CFLAGS = @sim_termio@
-DEVZERO_CFLAGS = @sim_devzero@
 CONFIG_CFLAGS = \
   $(SMP_CFLAGS) \
   $(XOR_ENDIAN_CFLAGS) \
@@ -84,8 +83,7 @@ CONFIG_CFLAGS = \
   $(FLOAT_CFLAGS) \
   $(MONITOR_CFLAGS) \
   $(MODEL_CFLAGS) \
-  $(TERMIO_CFLAGS) \
+  $(TERMIO_CFLAGS)
-  $(DEVZERO_CFLAGS)
 SIM_FPU_CFLAGS = -DHAVE_COMMON_FPU -I../common -I${srcdir}/../common
 
 STD_CFLAGS	= $(CFLAGS) $(WERROR_CFLAGS) $(INLINE_CFLAGS) $(CONFIG_CFLAGS) $(WARN_CFLAGS) $(INCLUDES) $(INCGNU) $(SIM_FPU_CFLAGS)

sim/ppc/configure

@@ -621,7 +621,6 @@ ac_includes_default="\
 
 ac_subst_vars='LTLIBOBJS
 LIBOBJS
-sim_devzero
 sim_termio
 sim_model_issue
 sim_default_model
@@ -4157,53 +4156,6 @@ _ACEOF
 fi
 
 
-sim_devzero=""
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for /dev/zero" >&5
-$as_echo_n "checking for /dev/zero... " >&6; }
-if ${ac_cv_devzero+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  if test "$cross_compiling" = yes; then :
-  ac_cv_devzero=no
-else
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <fcntl.h>
-main () {
-  char buf[2048];
-  int i;
-  int fd = open ("/dev/zero", O_RDONLY);
-  if (fd < 0)
-    return 1;
-  for (i = 0; i < sizeof (buf); i++)
-    buf[i] = 1;
-  if (read (fd, buf, sizeof (buf)) != sizeof (buf))
-    return 1;
-  for (i = 0; i < sizeof (buf); i++)
-    if (buf[i])
-      return 1;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_run "$LINENO"; then :
-  ac_cv_devzero=yes
-else
-  ac_cv_devzero=no
-fi
-rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
-  conftest.$ac_objext conftest.beam conftest.$ac_ext
-fi
-
-fi
-
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_devzero" >&5
-$as_echo "$ac_cv_devzero" >&6; }
-if test $ac_cv_devzero = yes; then
-  sim_devzero="-DHAVE_DEVZERO"
-else
-  sim_devzero=""
-fi
-
 # Since we run commands on the build system, we have to create a
 # separate config header for the build system if build != host.
 if test x$host = x$build; then
@@ -4257,7 +4209,6 @@ fi
 
 
 
-
 
 
 ac_config_files="$ac_config_files Makefile"

sim/ppc/configure.ac

@@ -490,33 +490,6 @@ fi
 
 AC_CHECK_TYPES(long long)
 
-dnl Figure out if /dev/zero exists or not
-sim_devzero=""
-AC_MSG_CHECKING(for /dev/zero)
-AC_CACHE_VAL(ac_cv_devzero,
-[AC_TRY_RUN([#include <fcntl.h>
-main () {
-  char buf[2048];
-  int i;
-  int fd = open ("/dev/zero", O_RDONLY);
-  if (fd < 0)
-    return 1;
-  for (i = 0; i < sizeof (buf); i++)
-    buf[i] = 1;
-  if (read (fd, buf, sizeof (buf)) != sizeof (buf))
-    return 1;
-  for (i = 0; i < sizeof (buf); i++)
-    if (buf[i])
-      return 1;
-  return 0;
-}],[ac_cv_devzero=yes],[ac_cv_devzero=no],[ac_cv_devzero=no])])
-AC_MSG_RESULT($ac_cv_devzero)
-if test $ac_cv_devzero = yes; then
-  sim_devzero="-DHAVE_DEVZERO"
-else
-  sim_devzero=""
-fi
-
 # Since we run commands on the build system, we have to create a
 # separate config header for the build system if build != host.
 if test x$host = x$build; then
@@ -570,7 +543,6 @@ AC_SUBST(sim_model)
 AC_SUBST(sim_default_model)
 AC_SUBST(sim_model_issue)
 AC_SUBST(sim_termio)
-AC_SUBST(sim_devzero)
 
 AC_OUTPUT(Makefile,
 [case x$CONFIG_HEADERS in xconfig.h:config.in) echo > stamp-h ;; esac])

sim/ppc/options.c

@@ -198,10 +198,6 @@ print_options (void)
 #ifdef HAVE_TERMIO_STRUCTURE
       "HAVE_TERMIO_STRUCTURE",
 #endif
-
-#ifdef HAVE_DEVZERO
-      "HAVE_DEVZERO",
-#endif
     };
 
     int i;