Ignore libedit/libreadline while probing for standard functions.

Some versions of libedit expose bogus definitions of setproctitle(),
optreset, and perhaps other symbols that we don't want configure to pick up
on.  There was a previous report of similar problems with strlcpy(), which
we addressed in commit 59cf88da91bc88978b05275ebd94ac2d980c4047, but the
problem has evidently grown in scope since then.  In hopes of not having to
deal with it again in future, rearrange configure's tests for supplied
functions so that we ignore libedit/libreadline except when probing
specifically for functions we expect them to provide.

Per report from Christoph Berg, though this is slightly more aggressive
than his proposed patch.

2 files changed, 283 insertions, 279 deletions

diff --git a/configure b/configure
index 3f56f8bc47..e3b2c64e42 100755
--- a/configure
+++ b/configure
@@ -15630,6 +15630,13 @@ fi
 
 
 
+# Some versions of libedit contain strlcpy(), setproctitle(), and other
+# symbols that that library has no business exposing to the world.  Pending
+# acquisition of a clue by those developers, ignore libedit (including its
+# possible alias of libreadline) while checking for everything else.
+LIBS_including_readline="$LIBS"
+LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
+
 
 
 
@@ -16802,11 +16809,6 @@ done
 
 fi
 
-# Some versions of libedit contain strlcpy(); so disregard that library while
-# checking for these standard libc functions.
-pgac_save_LIBS="$LIBS"
-LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
-
 
 
 
@@ -16928,8 +16930,6 @@ done
 
 
 
-LIBS="$pgac_save_LIBS"
-
 # System's version of getaddrinfo(), if any, may be used only if we found
 # a definition for struct addrinfo; see notes in src/include/getaddrinfo.h.
 # (Note: the AC_REPLACE_FUNCS probe fails on Windows, where the available
@@ -17366,264 +17366,6 @@ _ACEOF
 
 fi
 
-if test "$with_readline" = yes; then
-  echo "$as_me:$LINENO: checking for rl_completion_append_character" >&5
-echo $ECHO_N "checking for rl_completion_append_character... $ECHO_C" >&6
-cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-#include <stdio.h>
-#ifdef HAVE_READLINE_READLINE_H
-# include <readline/readline.h>
-#elif defined(HAVE_READLINE_H)
-# include <readline.h>
-#endif
-
-int
-main ()
-{
-rl_completion_append_character = 'x';
-  ;
-  return 0;
-}
-_ACEOF
-rm -f conftest.$ac_objext conftest$ac_exeext
-if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
-  (eval $ac_link) 2>conftest.er1
-  ac_status=$?
-  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_exeext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  echo "$as_me:$LINENO: result: yes" >&5
-echo "${ECHO_T}yes" >&6
-
-cat >>confdefs.h <<\_ACEOF
-#define HAVE_RL_COMPLETION_APPEND_CHARACTER 1
-_ACEOF
-
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-echo "$as_me:$LINENO: result: no" >&5
-echo "${ECHO_T}no" >&6
-fi
-rm -f conftest.err conftest.$ac_objext \
-      conftest$ac_exeext conftest.$ac_ext
-
-
-for ac_func in rl_completion_matches rl_filename_completion_function
-do
-as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
-echo "$as_me:$LINENO: checking for $ac_func" >&5
-echo $ECHO_N "checking for $ac_func... $ECHO_C" >&6
-if eval "test \"\${$as_ac_var+set}\" = set"; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-/* Define $ac_func to an innocuous variant, in case <limits.h> declares $ac_func.
-   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
-#define $ac_func innocuous_$ac_func
-
-/* System header to define __stub macros and hopefully few prototypes,
-    which can conflict with char $ac_func (); below.
-    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
-    <limits.h> exists even on freestanding compilers.  */
-
-#ifdef __STDC__
-# include <limits.h>
-#else
-# include <assert.h>
-#endif
-
-#undef $ac_func
-
-/* Override any GCC internal prototype to avoid an error.
-   Use char because int might match the return type of a GCC
-   builtin and then its argument prototype would still apply.  */
-#ifdef __cplusplus
-extern "C"
-#endif
-char $ac_func ();
-/* The GNU C library defines this for functions which it implements
-    to always fail with ENOSYS.  Some functions are actually named
-    something starting with __ and the normal name is an alias.  */
-#if defined __stub_$ac_func || defined __stub___$ac_func
-choke me
-#endif
-
-int
-main ()
-{
-return $ac_func ();
-  ;
-  return 0;
-}
-_ACEOF
-rm -f conftest.$ac_objext conftest$ac_exeext
-if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
-  (eval $ac_link) 2>conftest.er1
-  ac_status=$?
-  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_exeext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  eval "$as_ac_var=yes"
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-eval "$as_ac_var=no"
-fi
-rm -f conftest.err conftest.$ac_objext \
-      conftest$ac_exeext conftest.$ac_ext
-fi
-echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_var'}'`" >&5
-echo "${ECHO_T}`eval echo '${'$as_ac_var'}'`" >&6
-if test `eval echo '${'$as_ac_var'}'` = yes; then
-  cat >>confdefs.h <<_ACEOF
-#define `echo "HAVE_$ac_func" | $as_tr_cpp` 1
-_ACEOF
-
-fi
-done
-
-
-for ac_func in replace_history_entry
-do
-as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
-echo "$as_me:$LINENO: checking for $ac_func" >&5
-echo $ECHO_N "checking for $ac_func... $ECHO_C" >&6
-if eval "test \"\${$as_ac_var+set}\" = set"; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-/* Define $ac_func to an innocuous variant, in case <limits.h> declares $ac_func.
-   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
-#define $ac_func innocuous_$ac_func
-
-/* System header to define __stub macros and hopefully few prototypes,
-    which can conflict with char $ac_func (); below.
-    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
-    <limits.h> exists even on freestanding compilers.  */
-
-#ifdef __STDC__
-# include <limits.h>
-#else
-# include <assert.h>
-#endif
-
-#undef $ac_func
-
-/* Override any GCC internal prototype to avoid an error.
-   Use char because int might match the return type of a GCC
-   builtin and then its argument prototype would still apply.  */
-#ifdef __cplusplus
-extern "C"
-#endif
-char $ac_func ();
-/* The GNU C library defines this for functions which it implements
-    to always fail with ENOSYS.  Some functions are actually named
-    something starting with __ and the normal name is an alias.  */
-#if defined __stub_$ac_func || defined __stub___$ac_func
-choke me
-#endif
-
-int
-main ()
-{
-return $ac_func ();
-  ;
-  return 0;
-}
-_ACEOF
-rm -f conftest.$ac_objext conftest$ac_exeext
-if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
-  (eval $ac_link) 2>conftest.er1
-  ac_status=$?
-  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_exeext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  eval "$as_ac_var=yes"
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-eval "$as_ac_var=no"
-fi
-rm -f conftest.err conftest.$ac_objext \
-      conftest$ac_exeext conftest.$ac_ext
-fi
-echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_var'}'`" >&5
-echo "${ECHO_T}`eval echo '${'$as_ac_var'}'`" >&6
-if test `eval echo '${'$as_ac_var'}'` = yes; then
-  cat >>confdefs.h <<_ACEOF
-#define `echo "HAVE_$ac_func" | $as_tr_cpp` 1
-_ACEOF
-
-fi
-done
-
-fi
-
-
 echo "$as_me:$LINENO: checking for sigsetjmp" >&5
 echo $ECHO_N "checking for sigsetjmp... $ECHO_C" >&6
 cat >conftest.$ac_ext <<_ACEOF
@@ -18690,6 +18432,266 @@ _ACEOF
 
 fi
 
+# Lastly, restore full LIBS list and check for readline/libedit symbols
+LIBS="$LIBS_including_readline"
+
+if test "$with_readline" = yes; then
+  echo "$as_me:$LINENO: checking for rl_completion_append_character" >&5
+echo $ECHO_N "checking for rl_completion_append_character... $ECHO_C" >&6
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#include <stdio.h>
+#ifdef HAVE_READLINE_READLINE_H
+# include <readline/readline.h>
+#elif defined(HAVE_READLINE_H)
+# include <readline.h>
+#endif
+
+int
+main ()
+{
+rl_completion_append_character = 'x';
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+  (eval $ac_link) 2>conftest.er1
+  ac_status=$?
+  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_exeext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_RL_COMPLETION_APPEND_CHARACTER 1
+_ACEOF
+
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6
+fi
+rm -f conftest.err conftest.$ac_objext \
+      conftest$ac_exeext conftest.$ac_ext
+
+
+for ac_func in rl_completion_matches rl_filename_completion_function
+do
+as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
+echo "$as_me:$LINENO: checking for $ac_func" >&5
+echo $ECHO_N "checking for $ac_func... $ECHO_C" >&6
+if eval "test \"\${$as_ac_var+set}\" = set"; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+/* Define $ac_func to an innocuous variant, in case <limits.h> declares $ac_func.
+   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
+#define $ac_func innocuous_$ac_func
+
+/* System header to define __stub macros and hopefully few prototypes,
+    which can conflict with char $ac_func (); below.
+    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+    <limits.h> exists even on freestanding compilers.  */
+
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+
+#undef $ac_func
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char $ac_func ();
+/* The GNU C library defines this for functions which it implements
+    to always fail with ENOSYS.  Some functions are actually named
+    something starting with __ and the normal name is an alias.  */
+#if defined __stub_$ac_func || defined __stub___$ac_func
+choke me
+#endif
+
+int
+main ()
+{
+return $ac_func ();
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+  (eval $ac_link) 2>conftest.er1
+  ac_status=$?
+  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_exeext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  eval "$as_ac_var=yes"
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+eval "$as_ac_var=no"
+fi
+rm -f conftest.err conftest.$ac_objext \
+      conftest$ac_exeext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_var'}'`" >&5
+echo "${ECHO_T}`eval echo '${'$as_ac_var'}'`" >&6
+if test `eval echo '${'$as_ac_var'}'` = yes; then
+  cat >>confdefs.h <<_ACEOF
+#define `echo "HAVE_$ac_func" | $as_tr_cpp` 1
+_ACEOF
+
+fi
+done
+
+
+for ac_func in replace_history_entry
+do
+as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
+echo "$as_me:$LINENO: checking for $ac_func" >&5
+echo $ECHO_N "checking for $ac_func... $ECHO_C" >&6
+if eval "test \"\${$as_ac_var+set}\" = set"; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+/* Define $ac_func to an innocuous variant, in case <limits.h> declares $ac_func.
+   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
+#define $ac_func innocuous_$ac_func
+
+/* System header to define __stub macros and hopefully few prototypes,
+    which can conflict with char $ac_func (); below.
+    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+    <limits.h> exists even on freestanding compilers.  */
+
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+
+#undef $ac_func
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char $ac_func ();
+/* The GNU C library defines this for functions which it implements
+    to always fail with ENOSYS.  Some functions are actually named
+    something starting with __ and the normal name is an alias.  */
+#if defined __stub_$ac_func || defined __stub___$ac_func
+choke me
+#endif
+
+int
+main ()
+{
+return $ac_func ();
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+  (eval $ac_link) 2>conftest.er1
+  ac_status=$?
+  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_exeext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  eval "$as_ac_var=yes"
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+eval "$as_ac_var=no"
+fi
+rm -f conftest.err conftest.$ac_objext \
+      conftest$ac_exeext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_var'}'`" >&5
+echo "${ECHO_T}`eval echo '${'$as_ac_var'}'`" >&6
+if test `eval echo '${'$as_ac_var'}'` = yes; then
+  cat >>confdefs.h <<_ACEOF
+#define `echo "HAVE_$ac_func" | $as_tr_cpp` 1
+_ACEOF
+
+fi
+done
+
+fi
+
 
 #
 # Pthreads
diff --git a/configure.in b/configure.in
index 492b73d3b5..7a651a6d2a 100644
--- a/configure.in
+++ b/configure.in
@@ -995,6 +995,13 @@ PGAC_VAR_INT_TIMEZONE
 AC_FUNC_ACCEPT_ARGTYPES
 PGAC_FUNC_GETTIMEOFDAY_1ARG
 
+# Some versions of libedit contain strlcpy(), setproctitle(), and other
+# symbols that that library has no business exposing to the world.  Pending
+# acquisition of a clue by those developers, ignore libedit (including its
+# possible alias of libreadline) while checking for everything else.
+LIBS_including_readline="$LIBS"
+LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
+
 AC_CHECK_FUNCS([cbrt dlopen fcvt fdatasync getpeereid getrlimit memmove poll pstat readlink setproctitle setsid sigprocmask symlink sysconf towlower utime utimes waitpid wcstombs])
 
 AC_CHECK_DECLS(fdatasync, [], [], [#include <unistd.h>])
@@ -1091,15 +1098,8 @@ else
   AC_CHECK_FUNCS([fpclass fp_class fp_class_d class], [break])
 fi
 
-# Some versions of libedit contain strlcpy(); so disregard that library while
-# checking for these standard libc functions.
-pgac_save_LIBS="$LIBS"
-LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
-
 AC_REPLACE_FUNCS([crypt fseeko getopt getrusage inet_aton random rint srandom strdup strerror strlcat strlcpy strtol strtoul unsetenv])
 
-LIBS="$pgac_save_LIBS"
-
 # System's version of getaddrinfo(), if any, may be used only if we found
 # a definition for struct addrinfo; see notes in src/include/getaddrinfo.h.
 # (Note: the AC_REPLACE_FUNCS probe fails on Windows, where the available
@@ -1148,13 +1148,6 @@ AC_DEFINE([HAVE_SYMLINK], 1,
           [Define to 1 if you have the `symlink' function.])
 fi
 
-if test "$with_readline" = yes; then
-  PGAC_VAR_RL_COMPLETION_APPEND_CHARACTER
-  AC_CHECK_FUNCS([rl_completion_matches rl_filename_completion_function])
-  AC_CHECK_FUNCS([replace_history_entry])
-fi
-
-
 dnl Cannot use AC_CHECK_FUNC because sigsetjmp may be a macro
 dnl (especially on GNU libc)
 dnl See also comments in c.h.
@@ -1201,6 +1194,15 @@ if test x"$pgac_cv_gcc_int_atomics" = x"yes"; then
   AC_DEFINE(HAVE_GCC_INT_ATOMICS, 1, [Define to 1 if you have __sync_lock_test_and_set(int *) and friends.])
 fi
 
+# Lastly, restore full LIBS list and check for readline/libedit symbols
+LIBS="$LIBS_including_readline"
+
+if test "$with_readline" = yes; then
+  PGAC_VAR_RL_COMPLETION_APPEND_CHARACTER
+  AC_CHECK_FUNCS([rl_completion_matches rl_filename_completion_function])
+  AC_CHECK_FUNCS([replace_history_entry])
+fi
+
 
 #
 # Pthreads