Adjust configure's handling of libedit to not look for a history.h file.

Per Bob Friesenhahn's report, this file is not supplied by some versions
of libedit, and even when it is supplied it seems to be just a link to
readline.h, so we don't need to include it anyway.
Also, ensure that we won't try to use a too-old version of Bison.
The previous coding would bleat but then use it anyway; better to invoke
the 'missing' script if any grammar files need to be rebuilt.

configure

@@ -4765,7 +4765,8 @@ echo "${ECHO_T}no" >&6
 
 
 
-for ac_prog in 'bison -y'
+if test -z "$YACC"; then
+  for ac_prog in 'bison -y'
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -4806,34 +4807,36 @@ fi
 done
 
 
-if test "$YACC"; then
-  if $YACC --version | sed q | $AWK '{ if ($4 < 1.875) exit 0; else exit 1;}'; then
-    { echo "$as_me:$LINENO: WARNING:
-*** If you are going to modify the grammar files or build from CVS, the installed
-*** version of Bison is too old.  Bison version 1.875 or later is required." >&5
+  if test "$YACC"; then
+    if $YACC --version | sed q | $AWK '{ if ($4 < 1.875) exit 0; else exit 1;}'; then
+      { echo "$as_me:$LINENO: WARNING:
+*** The installed version of Bison is too old to use with PostgreSQL.
+*** Bison version 1.875 or later is required." >&5
 echo "$as_me: WARNING:
-*** If you are going to modify the grammar files or build from CVS, the installed
-*** version of Bison is too old.  Bison version 1.875 or later is required." >&2;}
+*** The installed version of Bison is too old to use with PostgreSQL.
+*** Bison version 1.875 or later is required." >&2;}
+      YACC=""
+    fi
   fi
-fi
 
-if test -z "$YACC"; then
-  { echo "$as_me:$LINENO: WARNING:
-*** Without Bison you will not be able to build PostgreSQL from CVS or
+  if test -z "$YACC"; then
+    { echo "$as_me:$LINENO: WARNING:
+*** Without Bison you will not be able to build PostgreSQL from CVS nor
 *** change any of the parser definition files.  You can obtain Bison from
 *** a GNU mirror site.  (If you are using the official distribution of
-*** PostgreSQL then you do not need to worry about this because the Bison
+*** PostgreSQL then you do not need to worry about this, because the Bison
 *** output is pre-generated.)  To use a different yacc program (possible,
 *** but not recommended), set the environment variable YACC before running
 *** 'configure'." >&5
 echo "$as_me: WARNING:
-*** Without Bison you will not be able to build PostgreSQL from CVS or
+*** Without Bison you will not be able to build PostgreSQL from CVS nor
 *** change any of the parser definition files.  You can obtain Bison from
 *** a GNU mirror site.  (If you are using the official distribution of
-*** PostgreSQL then you do not need to worry about this because the Bison
+*** PostgreSQL then you do not need to worry about this, because the Bison
 *** output is pre-generated.)  To use a different yacc program (possible,
 *** but not recommended), set the environment variable YACC before running
 *** 'configure'." >&2;}
+  fi
 fi
 
 
@@ -9046,468 +9049,10 @@ fi
 
 done
 
-
-for ac_header in editline/history.h
-do
-as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
-if eval "test \"\${$as_ac_Header+set}\" = set"; then
-  echo "$as_me:$LINENO: checking for $ac_header" >&5
-echo $ECHO_N "checking for $ac_header... $ECHO_C" >&6
-if eval "test \"\${$as_ac_Header+set}\" = set"; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-fi
-echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_Header'}'`" >&5
-echo "${ECHO_T}`eval echo '${'$as_ac_Header'}'`" >&6
-else
-  # Is the header compilable?
-echo "$as_me:$LINENO: checking $ac_header usability" >&5
-echo $ECHO_N "checking $ac_header usability... $ECHO_C" >&6
-cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-$ac_includes_default
-#include <$ac_header>
-_ACEOF
-rm -f conftest.$ac_objext
-if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
-  (eval $ac_compile) 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } &&
-	 { ac_try='test -z "$ac_c_werror_flag"
-			 || test ! -s conftest.err'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; } &&
-	 { ac_try='test -s conftest.$ac_objext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  ac_header_compiler=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-ac_header_compiler=no
-fi
-rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-echo "$as_me:$LINENO: result: $ac_header_compiler" >&5
-echo "${ECHO_T}$ac_header_compiler" >&6
-
-# Is the header present?
-echo "$as_me:$LINENO: checking $ac_header presence" >&5
-echo $ECHO_N "checking $ac_header presence... $ECHO_C" >&6
-cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-#include <$ac_header>
-_ACEOF
-if { (eval echo "$as_me:$LINENO: \"$ac_cpp conftest.$ac_ext\"") >&5
-  (eval $ac_cpp conftest.$ac_ext) 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } >/dev/null; then
-  if test -s conftest.err; then
-    ac_cpp_err=$ac_c_preproc_warn_flag
-    ac_cpp_err=$ac_cpp_err$ac_c_werror_flag
-  else
-    ac_cpp_err=
-  fi
-else
-  ac_cpp_err=yes
-fi
-if test -z "$ac_cpp_err"; then
-  ac_header_preproc=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-  ac_header_preproc=no
-fi
-rm -f conftest.err conftest.$ac_ext
-echo "$as_me:$LINENO: result: $ac_header_preproc" >&5
-echo "${ECHO_T}$ac_header_preproc" >&6
-
-# So?  What about this header?
-case $ac_header_compiler:$ac_header_preproc:$ac_c_preproc_warn_flag in
-  yes:no: )
-    { echo "$as_me:$LINENO: WARNING: $ac_header: accepted by the compiler, rejected by the preprocessor!" >&5
-echo "$as_me: WARNING: $ac_header: accepted by the compiler, rejected by the preprocessor!" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: proceeding with the compiler's result" >&5
-echo "$as_me: WARNING: $ac_header: proceeding with the compiler's result" >&2;}
-    ac_header_preproc=yes
-    ;;
-  no:yes:* )
-    { echo "$as_me:$LINENO: WARNING: $ac_header: present but cannot be compiled" >&5
-echo "$as_me: WARNING: $ac_header: present but cannot be compiled" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header:     check for missing prerequisite headers?" >&5
-echo "$as_me: WARNING: $ac_header:     check for missing prerequisite headers?" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: see the Autoconf documentation" >&5
-echo "$as_me: WARNING: $ac_header: see the Autoconf documentation" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header:     section \"Present But Cannot Be Compiled\"" >&5
-echo "$as_me: WARNING: $ac_header:     section \"Present But Cannot Be Compiled\"" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: proceeding with the preprocessor's result" >&5
-echo "$as_me: WARNING: $ac_header: proceeding with the preprocessor's result" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: in the future, the compiler will take precedence" >&5
-echo "$as_me: WARNING: $ac_header: in the future, the compiler will take precedence" >&2;}
-    (
-      cat <<\_ASBOX
-## ---------------------------------------- ##
-## Report this to pgsql-bugs@postgresql.org ##
-## ---------------------------------------- ##
-_ASBOX
-    ) |
-      sed "s/^/$as_me: WARNING:     /" >&2
-    ;;
-esac
-echo "$as_me:$LINENO: checking for $ac_header" >&5
-echo $ECHO_N "checking for $ac_header... $ECHO_C" >&6
-if eval "test \"\${$as_ac_Header+set}\" = set"; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  eval "$as_ac_Header=\$ac_header_preproc"
-fi
-echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_Header'}'`" >&5
-echo "${ECHO_T}`eval echo '${'$as_ac_Header'}'`" >&6
-
-fi
-if test `eval echo '${'$as_ac_Header'}'` = yes; then
-  cat >>confdefs.h <<_ACEOF
-#define `echo "HAVE_$ac_header" | $as_tr_cpp` 1
-_ACEOF
-
-else
-
-for ac_header in history.h
-do
-as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
-if eval "test \"\${$as_ac_Header+set}\" = set"; then
-  echo "$as_me:$LINENO: checking for $ac_header" >&5
-echo $ECHO_N "checking for $ac_header... $ECHO_C" >&6
-if eval "test \"\${$as_ac_Header+set}\" = set"; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-fi
-echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_Header'}'`" >&5
-echo "${ECHO_T}`eval echo '${'$as_ac_Header'}'`" >&6
-else
-  # Is the header compilable?
-echo "$as_me:$LINENO: checking $ac_header usability" >&5
-echo $ECHO_N "checking $ac_header usability... $ECHO_C" >&6
-cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-$ac_includes_default
-#include <$ac_header>
-_ACEOF
-rm -f conftest.$ac_objext
-if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
-  (eval $ac_compile) 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } &&
-	 { ac_try='test -z "$ac_c_werror_flag"
-			 || test ! -s conftest.err'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; } &&
-	 { ac_try='test -s conftest.$ac_objext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  ac_header_compiler=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-ac_header_compiler=no
-fi
-rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-echo "$as_me:$LINENO: result: $ac_header_compiler" >&5
-echo "${ECHO_T}$ac_header_compiler" >&6
-
-# Is the header present?
-echo "$as_me:$LINENO: checking $ac_header presence" >&5
-echo $ECHO_N "checking $ac_header presence... $ECHO_C" >&6
-cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-#include <$ac_header>
-_ACEOF
-if { (eval echo "$as_me:$LINENO: \"$ac_cpp conftest.$ac_ext\"") >&5
-  (eval $ac_cpp conftest.$ac_ext) 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } >/dev/null; then
-  if test -s conftest.err; then
-    ac_cpp_err=$ac_c_preproc_warn_flag
-    ac_cpp_err=$ac_cpp_err$ac_c_werror_flag
-  else
-    ac_cpp_err=
-  fi
-else
-  ac_cpp_err=yes
-fi
-if test -z "$ac_cpp_err"; then
-  ac_header_preproc=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-  ac_header_preproc=no
-fi
-rm -f conftest.err conftest.$ac_ext
-echo "$as_me:$LINENO: result: $ac_header_preproc" >&5
-echo "${ECHO_T}$ac_header_preproc" >&6
-
-# So?  What about this header?
-case $ac_header_compiler:$ac_header_preproc:$ac_c_preproc_warn_flag in
-  yes:no: )
-    { echo "$as_me:$LINENO: WARNING: $ac_header: accepted by the compiler, rejected by the preprocessor!" >&5
-echo "$as_me: WARNING: $ac_header: accepted by the compiler, rejected by the preprocessor!" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: proceeding with the compiler's result" >&5
-echo "$as_me: WARNING: $ac_header: proceeding with the compiler's result" >&2;}
-    ac_header_preproc=yes
-    ;;
-  no:yes:* )
-    { echo "$as_me:$LINENO: WARNING: $ac_header: present but cannot be compiled" >&5
-echo "$as_me: WARNING: $ac_header: present but cannot be compiled" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header:     check for missing prerequisite headers?" >&5
-echo "$as_me: WARNING: $ac_header:     check for missing prerequisite headers?" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: see the Autoconf documentation" >&5
-echo "$as_me: WARNING: $ac_header: see the Autoconf documentation" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header:     section \"Present But Cannot Be Compiled\"" >&5
-echo "$as_me: WARNING: $ac_header:     section \"Present But Cannot Be Compiled\"" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: proceeding with the preprocessor's result" >&5
-echo "$as_me: WARNING: $ac_header: proceeding with the preprocessor's result" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: in the future, the compiler will take precedence" >&5
-echo "$as_me: WARNING: $ac_header: in the future, the compiler will take precedence" >&2;}
-    (
-      cat <<\_ASBOX
-## ---------------------------------------- ##
-## Report this to pgsql-bugs@postgresql.org ##
-## ---------------------------------------- ##
-_ASBOX
-    ) |
-      sed "s/^/$as_me: WARNING:     /" >&2
-    ;;
-esac
-echo "$as_me:$LINENO: checking for $ac_header" >&5
-echo $ECHO_N "checking for $ac_header... $ECHO_C" >&6
-if eval "test \"\${$as_ac_Header+set}\" = set"; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  eval "$as_ac_Header=\$ac_header_preproc"
-fi
-echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_Header'}'`" >&5
-echo "${ECHO_T}`eval echo '${'$as_ac_Header'}'`" >&6
-
-fi
-if test `eval echo '${'$as_ac_Header'}'` = yes; then
-  cat >>confdefs.h <<_ACEOF
-#define `echo "HAVE_$ac_header" | $as_tr_cpp` 1
-_ACEOF
-
-else
-
-for ac_header in readline/history.h
-do
-as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
-if eval "test \"\${$as_ac_Header+set}\" = set"; then
-  echo "$as_me:$LINENO: checking for $ac_header" >&5
-echo $ECHO_N "checking for $ac_header... $ECHO_C" >&6
-if eval "test \"\${$as_ac_Header+set}\" = set"; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-fi
-echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_Header'}'`" >&5
-echo "${ECHO_T}`eval echo '${'$as_ac_Header'}'`" >&6
-else
-  # Is the header compilable?
-echo "$as_me:$LINENO: checking $ac_header usability" >&5
-echo $ECHO_N "checking $ac_header usability... $ECHO_C" >&6
-cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-$ac_includes_default
-#include <$ac_header>
-_ACEOF
-rm -f conftest.$ac_objext
-if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
-  (eval $ac_compile) 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } &&
-	 { ac_try='test -z "$ac_c_werror_flag"
-			 || test ! -s conftest.err'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; } &&
-	 { ac_try='test -s conftest.$ac_objext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  ac_header_compiler=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-ac_header_compiler=no
-fi
-rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-echo "$as_me:$LINENO: result: $ac_header_compiler" >&5
-echo "${ECHO_T}$ac_header_compiler" >&6
-
-# Is the header present?
-echo "$as_me:$LINENO: checking $ac_header presence" >&5
-echo $ECHO_N "checking $ac_header presence... $ECHO_C" >&6
-cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-#include <$ac_header>
-_ACEOF
-if { (eval echo "$as_me:$LINENO: \"$ac_cpp conftest.$ac_ext\"") >&5
-  (eval $ac_cpp conftest.$ac_ext) 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } >/dev/null; then
-  if test -s conftest.err; then
-    ac_cpp_err=$ac_c_preproc_warn_flag
-    ac_cpp_err=$ac_cpp_err$ac_c_werror_flag
-  else
-    ac_cpp_err=
-  fi
-else
-  ac_cpp_err=yes
-fi
-if test -z "$ac_cpp_err"; then
-  ac_header_preproc=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-  ac_header_preproc=no
-fi
-rm -f conftest.err conftest.$ac_ext
-echo "$as_me:$LINENO: result: $ac_header_preproc" >&5
-echo "${ECHO_T}$ac_header_preproc" >&6
-
-# So?  What about this header?
-case $ac_header_compiler:$ac_header_preproc:$ac_c_preproc_warn_flag in
-  yes:no: )
-    { echo "$as_me:$LINENO: WARNING: $ac_header: accepted by the compiler, rejected by the preprocessor!" >&5
-echo "$as_me: WARNING: $ac_header: accepted by the compiler, rejected by the preprocessor!" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: proceeding with the compiler's result" >&5
-echo "$as_me: WARNING: $ac_header: proceeding with the compiler's result" >&2;}
-    ac_header_preproc=yes
-    ;;
-  no:yes:* )
-    { echo "$as_me:$LINENO: WARNING: $ac_header: present but cannot be compiled" >&5
-echo "$as_me: WARNING: $ac_header: present but cannot be compiled" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header:     check for missing prerequisite headers?" >&5
-echo "$as_me: WARNING: $ac_header:     check for missing prerequisite headers?" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: see the Autoconf documentation" >&5
-echo "$as_me: WARNING: $ac_header: see the Autoconf documentation" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header:     section \"Present But Cannot Be Compiled\"" >&5
-echo "$as_me: WARNING: $ac_header:     section \"Present But Cannot Be Compiled\"" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: proceeding with the preprocessor's result" >&5
-echo "$as_me: WARNING: $ac_header: proceeding with the preprocessor's result" >&2;}
-    { echo "$as_me:$LINENO: WARNING: $ac_header: in the future, the compiler will take precedence" >&5
-echo "$as_me: WARNING: $ac_header: in the future, the compiler will take precedence" >&2;}
-    (
-      cat <<\_ASBOX
-## ---------------------------------------- ##
-## Report this to pgsql-bugs@postgresql.org ##
-## ---------------------------------------- ##
-_ASBOX
-    ) |
-      sed "s/^/$as_me: WARNING:     /" >&2
-    ;;
-esac
-echo "$as_me:$LINENO: checking for $ac_header" >&5
-echo $ECHO_N "checking for $ac_header... $ECHO_C" >&6
-if eval "test \"\${$as_ac_Header+set}\" = set"; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  eval "$as_ac_Header=\$ac_header_preproc"
-fi
-echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_Header'}'`" >&5
-echo "${ECHO_T}`eval echo '${'$as_ac_Header'}'`" >&6
-
-fi
-if test `eval echo '${'$as_ac_Header'}'` = yes; then
-  cat >>confdefs.h <<_ACEOF
-#define `echo "HAVE_$ac_header" | $as_tr_cpp` 1
-_ACEOF
-
-else
-  { { echo "$as_me:$LINENO: error: history header not found
-If you have libedit already installed, see config.log for details on the
-failure.  It is possible the compiler isn't looking in the proper directory.
-Use --without-readline to disable libedit support." >&5
-echo "$as_me: error: history header not found
-If you have libedit already installed, see config.log for details on the
-failure.  It is possible the compiler isn't looking in the proper directory.
-Use --without-readline to disable libedit support." >&2;}
-   { (exit 1); exit 1; }; }
-fi
-
-done
-
-fi
-
-done
-
-fi
-
-done
-
+# Note: in a libedit installation, history.h is normally a dummy, and may
+# not be there at all.  The functions are declared in readline.h instead.
+# To avoid including incompatible headers when both libraries are present,
+# assume we do not need history.h.
 fi
 
 if test "$with_zlib" = yes; then

configure.in

 dnl Process this file with autoconf to produce a configure script.
-dnl $PostgreSQL: pgsql/configure.in,v 1.479 2006/10/03 22:18:22 tgl Exp $
+dnl $PostgreSQL: pgsql/configure.in,v 1.480 2006/10/04 22:31:13 tgl Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -594,25 +594,28 @@ AC_PROG_RANLIB
 AC_PATH_PROG(TAR, tar)
 PGAC_CHECK_STRIP
 
-AC_CHECK_PROGS(YACC, ['bison -y'])
-
-if test "$YACC"; then
-  if $YACC --version | sed q | $AWK '{ if ($4 < 1.875) exit 0; else exit 1;}'; then
-    AC_MSG_WARN([
-*** If you are going to modify the grammar files or build from CVS, the installed
-*** version of Bison is too old.  Bison version 1.875 or later is required.])
+if test -z "$YACC"; then
+  AC_CHECK_PROGS(YACC, ['bison -y'])
+
+  if test "$YACC"; then
+    if $YACC --version | sed q | $AWK '{ if ($4 < 1.875) exit 0; else exit 1;}'; then
+      AC_MSG_WARN([
+*** The installed version of Bison is too old to use with PostgreSQL.
+*** Bison version 1.875 or later is required.])
+      YACC=""
+    fi
   fi
-fi
 
-if test -z "$YACC"; then
-  AC_MSG_WARN([
-*** Without Bison you will not be able to build PostgreSQL from CVS or
+  if test -z "$YACC"; then
+    AC_MSG_WARN([
+*** Without Bison you will not be able to build PostgreSQL from CVS nor
 *** change any of the parser definition files.  You can obtain Bison from
 *** a GNU mirror site.  (If you are using the official distribution of
-*** PostgreSQL then you do not need to worry about this because the Bison
+*** PostgreSQL then you do not need to worry about this, because the Bison
 *** output is pre-generated.)  To use a different yacc program (possible,
 *** but not recommended), set the environment variable YACC before running
 *** 'configure'.])
+  fi
 fi
 AC_SUBST(YFLAGS)
 
@@ -753,13 +756,10 @@ if expr x"$pgac_cv_check_readline" : 'x-ledit' >/dev/null ; then
 If you have libedit already installed, see config.log for details on the
 failure.  It is possible the compiler isn't looking in the proper directory.
 Use --without-readline to disable libedit support.])])])])
-  AC_CHECK_HEADERS(editline/history.h, [],
-        [AC_CHECK_HEADERS(history.h, [],
-                [AC_CHECK_HEADERS(readline/history.h, [],
-                        [AC_MSG_ERROR([history header not found
-If you have libedit already installed, see config.log for details on the
-failure.  It is possible the compiler isn't looking in the proper directory.
-Use --without-readline to disable libedit support.])])])])
+# Note: in a libedit installation, history.h is normally a dummy, and may
+# not be there at all.  The functions are declared in readline.h instead.
+# To avoid including incompatible headers when both libraries are present,
+# assume we do not need history.h.
 fi
 
 if test "$with_zlib" = yes; then

src/include/pg_config.h.in

@@ -101,9 +101,6 @@
 /* Define to 1 if you have the `dlopen' function. */
 #undef HAVE_DLOPEN
 
-/* Define to 1 if you have the <editline/history.h> header file. */
-#undef HAVE_EDITLINE_HISTORY_H
-
 /* Define to 1 if you have the <editline/readline.h> header file. */
 #undef HAVE_EDITLINE_READLINE_H