Fix readline/libedit selection code to prefer readline over libedit

reliably (ie, regardless of which libraries they depend on).  Also
make sure that we don't select headers that obviously belong to the
wrong one of the two libraries.  This was discussed back around 4-Sep
but seems to have slipped through the cracks.  The header selection
could be checked more closely, perhaps, but let's see if this is good
enough.

3 files changed, 296 insertions, 34 deletions

diff --git a/config/programs.m4 b/config/programs.m4
index c67b9f18eb..9182a0972b 100644
--- a/config/programs.m4
+++ b/config/programs.m4
@@ -82,10 +82,10 @@ AC_MSG_CHECKING([for readline])
 
 AC_CACHE_VAL([pgac_cv_check_readline],
 [pgac_cv_check_readline=no
-for pgac_lib in "" " -ltermcap" " -lncurses" " -lcurses" ; do
-  for pgac_rllib in -lreadline -ledit ; do
-    pgac_save_LIBS=$LIBS
-    LIBS="${pgac_rllib}${pgac_lib} $LIBS"
+pgac_save_LIBS=$LIBS
+for pgac_rllib in -lreadline -ledit ; do
+  for pgac_lib in "" " -ltermcap" " -lncurses" " -lcurses" ; do
+    LIBS="${pgac_rllib}${pgac_lib} $pgac_save_LIBS"
     AC_TRY_LINK_FUNC([readline], [[
       # NetBSD, OpenBSD, and Irix have a broken linker that does not
       # recognize dependent libraries
@@ -99,7 +99,6 @@ for pgac_lib in "" " -ltermcap" " -lncurses" " -lcurses" ; do
       pgac_cv_check_readline="${pgac_rllib}${pgac_lib}"
       break 2
     ]])
-    LIBS=$pgac_save_LIBS
   done
 done
 LIBS=$pgac_save_LIBS
diff --git a/configure b/configure
index 8fb1aff2d6..009714367f 100755
--- a/configure
+++ b/configure
@@ -5954,10 +5954,10 @@ if test "${pgac_cv_check_readline+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
   pgac_cv_check_readline=no
-for pgac_lib in "" " -ltermcap" " -lncurses" " -lcurses" ; do
-  for pgac_rllib in -lreadline -ledit ; do
-    pgac_save_LIBS=$LIBS
-    LIBS="${pgac_rllib}${pgac_lib} $LIBS"
+pgac_save_LIBS=$LIBS
+for pgac_rllib in -lreadline -ledit ; do
+  for pgac_lib in "" " -ltermcap" " -lncurses" " -lcurses" ; do
+    LIBS="${pgac_rllib}${pgac_lib} $pgac_save_LIBS"
     cat >conftest.$ac_ext <<_ACEOF
 #line $LINENO "configure"
 #include "confdefs.h"
@@ -6013,7 +6013,6 @@ else
 cat conftest.$ac_ext >&5
 fi
 rm -f conftest.$ac_objext conftest$ac_exeext conftest.$ac_ext
-    LIBS=$pgac_save_LIBS
   done
 done
 LIBS=$pgac_save_LIBS
@@ -7559,7 +7558,7 @@ fi
 done
 
 
-if test "$with_readline" = yes; then
+if expr x"$pgac_cv_check_readline" : 'x-lreadline' >/dev/null ; then
 
 for ac_header in readline/readline.h
 do
@@ -7672,7 +7671,7 @@ _ACEOF
 
 else
 
-for ac_header in editline/readline.h
+for ac_header in readline.h
 do
 as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
 if eval "test \"\${$as_ac_Header+set}\" = set"; then
@@ -7782,8 +7781,25 @@ if test `eval echo '${'$as_ac_Header'}'` = yes; then
 _ACEOF
 
 else
+  { { echo "$as_me:$LINENO: error: readline header not found
+If you have readline 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 readline support." >&5
+echo "$as_me: error: readline header not found
+If you have readline 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 readline support." >&2;}
+   { (exit 1); exit 1; }; }
+fi
 
-for ac_header in readline.h
+done
+
+fi
+
+done
+
+
+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
@@ -7893,11 +7909,122 @@ if test `eval echo '${'$as_ac_Header'}'` = yes; then
 _ACEOF
 
 else
-  { { echo "$as_me:$LINENO: error: readline header not found
+
+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
+#line $LINENO "configure"
+#include "confdefs.h"
+$ac_includes_default
+#include <$ac_header>
+_ACEOF
+rm -f conftest.$ac_objext
+if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  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
+cat conftest.$ac_ext >&5
+ac_header_compiler=no
+fi
+rm -f conftest.$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
+#line $LINENO "configure"
+#include "confdefs.h"
+#include <$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=$?
+  egrep -v '^ *\+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$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
+  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
+  cat 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 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: $ac_header: proceeding with the preprocessor's result" >&5
+echo "$as_me: WARNING: $ac_header: proceeding with the preprocessor's result" >&2;};;
+  no:yes )
+    { echo "$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: $ac_header: proceeding with the preprocessor's result" >&5
+echo "$as_me: WARNING: $ac_header: proceeding with the preprocessor's result" >&2;};;
+esac
+echo "$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:$LINENO: error: history header not found
 If you have readline already installed, see config.log for details on the
 failure.  It is possible the compiler isn't looking in the proper directory.
 Use --without-readline to disable readline support." >&5
-echo "$as_me: error: readline header not found
+echo "$as_me: error: history header not found
 If you have readline 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 readline support." >&2;}
@@ -7912,10 +8039,120 @@ done
 
 fi
 
-done
+if expr x"$pgac_cv_check_readline" : 'x-ledit' >/dev/null ; then
 
+for ac_header in editline/readline.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
+#line $LINENO "configure"
+#include "confdefs.h"
+$ac_includes_default
+#include <$ac_header>
+_ACEOF
+rm -f conftest.$ac_objext
+if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  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
+cat conftest.$ac_ext >&5
+ac_header_compiler=no
+fi
+rm -f conftest.$ac_objext conftest.$ac_ext
+echo "$as_me:$LINENO: result: $ac_header_compiler" >&5
+echo "${ECHO_T}$ac_header_compiler" >&6
 
-for ac_header in readline/history.h
+# 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
+#line $LINENO "configure"
+#include "confdefs.h"
+#include <$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=$?
+  egrep -v '^ *\+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$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
+  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
+  cat 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 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: $ac_header: proceeding with the preprocessor's result" >&5
+echo "$as_me: WARNING: $ac_header: proceeding with the preprocessor's result" >&2;};;
+  no:yes )
+    { echo "$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: $ac_header: proceeding with the preprocessor's result" >&5
+echo "$as_me: WARNING: $ac_header: proceeding with the preprocessor's result" >&2;};;
+esac
+echo "$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" | $as_tr_cpp` 1
+_ACEOF
+
+else
+
+for ac_header in readline.h
 do
 as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
 if eval "test \"\${$as_ac_Header+set}\" = set"; then
@@ -8025,6 +8262,23 @@ if test `eval echo '${'$as_ac_Header'}'` = yes; then
 _ACEOF
 
 else
+  { { echo "$as_me:$LINENO: error: readline 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: readline 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
+
 
 for ac_header in editline/history.h
 do
@@ -8248,13 +8502,13 @@ _ACEOF
 
 else
   { { echo "$as_me:$LINENO: error: history header not found
-If you have readline already installed, see config.log for details on the
+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 readline support." >&5
+Use --without-readline to disable libedit support." >&5
 echo "$as_me: error: history header not found
-If you have readline already installed, see config.log for details on the
+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 readline support." >&2;}
+Use --without-readline to disable libedit support." >&2;}
    { (exit 1); exit 1; }; }
 fi
 
@@ -8266,10 +8520,6 @@ done
 
 fi
 
-done
-
-fi
-
 if test "$with_zlib" = yes; then
   if test "${ac_cv_header_zlib_h+set}" = set; then
   echo "$as_me:$LINENO: checking for zlib.h" >&5
diff --git a/configure.in b/configure.in
index e15fc7ad6e..083c3cf2c2 100644
--- a/configure.in
+++ b/configure.in
@@ -714,21 +714,34 @@ AC_CHECK_HEADERS(netinet/tcp.h, [], [],
 #endif
 ])
 
-if test "$with_readline" = yes; then
+if expr x"$pgac_cv_check_readline" : 'x-lreadline' >/dev/null ; then
   AC_CHECK_HEADERS(readline/readline.h, [],
-                   [AC_CHECK_HEADERS(editline/readline.h, [],
-                         [AC_CHECK_HEADERS(readline.h, [],
-                                     [AC_MSG_ERROR([readline header not found
+                   [AC_CHECK_HEADERS(readline.h, [],
+                                [AC_MSG_ERROR([readline header not found
 If you have readline 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 readline support.])])])])
+Use --without-readline to disable readline support.])])])
   AC_CHECK_HEADERS(readline/history.h, [],
-                   [AC_CHECK_HEADERS(editline/history.h, [],
-                         [AC_CHECK_HEADERS(history.h, [],
-                                     [AC_MSG_ERROR([history header not found
+                   [AC_CHECK_HEADERS(history.h, [],
+                                [AC_MSG_ERROR([history header not found
 If you have readline 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 readline support.])])])])
+Use --without-readline to disable readline support.])])])
+fi
+
+if expr x"$pgac_cv_check_readline" : 'x-ledit' >/dev/null ; then
+  AC_CHECK_HEADERS(editline/readline.h, [],
+                   [AC_CHECK_HEADERS(readline.h, [],
+                                [AC_MSG_ERROR([readline 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.])])])
+  AC_CHECK_HEADERS(editline/history.h, [],
+                   [AC_CHECK_HEADERS(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.])])])
 fi
 
 if test "$with_zlib" = yes; then