bpo-13501: allow choosing between readline and libedit (GH-24189)

In contrast to macOS, libedit is available as its own include file and
library on Linux systems to prevent file name clashes. So if both
libraries are available on the system, readline is currently chosen by
default; and if only libedit is available, it is not found at all. This
patch adds a way to link against libedit by adding the following
arguments to configure:

  --with-readline           link against libreadline (the default)
  --with-readline=editline  link against libeditline
  --with-readline=no        disable building the readline module
  --without-readline        (same)

The runtime detection of libedit vs. readline was already done in commit
7105319ada (2019-12-04, serge-sans-paille: "bpo-38634: Allow
non-apple build to cope with libedit (GH-16986)").

Fixes: GH-12076 ("bpo-13501 Build or disable readline with Editline")
Fixes: bpo-13501 ("Make libedit support more generic; port readline / libedit to FreeBSD")
Co-authored-by: Enji Cooper (ngie-eign)
Co-authored-by: Martin Panter (vadmium)
Co-authored-by: Robert Marshall (kellinm)

Misc/NEWS.d/next/Build/2021-01-10-22-25-23.bpo-13501.g4L-6R.rst

@@ -0,0 +1,2 @@
+The configure script can now use *libedit* instead of *readline* with the
+command line option ``--with-readline=editline``.

Modules/readline.c

@@ -26,10 +26,14 @@
 #  define RESTORE_LOCALE(sl)
 #endif
 
+#ifdef WITH_EDITLINE
+#  include <editline/readline.h>
+#else
 /* GNU readline definitions */
 #  undef HAVE_CONFIG_H /* Else readline/chardefs.h includes strings.h */
 #  include <readline/readline.h>
 #  include <readline/history.h>
+#endif
 
 #ifdef HAVE_RL_COMPLETION_MATCHES
 #define completion_matches(x, y) \

configure

@@ -849,6 +849,7 @@ with_libc
 enable_big_digits
 with_platlibdir
 with_wheel_pkg_dir
+with_readline
 with_computed_gotos
 with_ensurepip
 with_openssl
@@ -1581,6 +1582,8 @@ Optional Packages:
   --with-wheel-pkg-dir=PATH
                           Directory of wheel packages used by ensurepip
                           (default: none)
+  --with(out)-readline[=editline]
+                          use Editline for backend or disable readline module
   --with-computed-gotos   enable computed gotos in evaluation loop (enabled by
                           default on supported compilers)
   --with-ensurepip[=install|upgrade|no]
@@ -15602,21 +15605,46 @@ $as_echo "#define HAVE_GETC_UNLOCKED 1" >>confdefs.h
 
 fi
 
+
+# Check whether --with-readline was given.
+if test "${with_readline+set}" = set; then :
+  withval=$with_readline;
+else
+  with_readline=yes
+fi
+
+
 # check where readline lives
+py_cv_lib_readline=no
 # save the value of LIBS so we don't actually link Python with readline
 LIBS_no_readline=$LIBS
 
+if test "$with_readline" != no; then
+  case "$with_readline" in
+  editline|edit)
+    LIBREADLINE=edit
+
+$as_echo "#define WITH_EDITLINE 1" >>confdefs.h
+
+    ;;
+  yes|readline)
+    LIBREADLINE=readline
+    ;;
+  *)
+    as_fn_error $? "proper usage is --with(out)-readline[=editline]" "$LINENO" 5
+    ;;
+  esac
+
   # On some systems we need to link readline to a termcap compatible
   # library.  NOTE: Keep the precedence of listed libraries synchronised
   # with setup.py.
-py_cv_lib_readline=no
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking how to link readline libs" >&5
 $as_echo_n "checking how to link readline libs... " >&6; }
   for py_libtermcap in "" tinfo ncursesw ncurses curses termcap; do
     if test -z "$py_libtermcap"; then
-    READLINE_LIBS="-lreadline"
+      READLINE_LIBS="-l$LIBREADLINE"
     else
-    READLINE_LIBS="-lreadline -l$py_libtermcap"
+      READLINE_LIBS="-l$LIBREADLINE -l$py_libtermcap"
     fi
     LIBS="$READLINE_LIBS $LIBS_no_readline"
     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -15646,7 +15674,8 @@ rm -f core conftest.err conftest.$ac_objext \
       break
     fi
   done
-# Uncomment this line if you want to use READINE_LIBS in Makefile or scripts
+
+  # Uncomment this line if you want to use READLINE_LIBS in Makefile or scripts
   #AC_SUBST([READLINE_LIBS])
   if test $py_cv_lib_readline = no; then
     { $as_echo "$as_me:${as_lineno-$LINENO}: result: none" >&5
@@ -15658,57 +15687,50 @@ $as_echo "$READLINE_LIBS" >&6; }
 $as_echo "#define HAVE_LIBREADLINE 1" >>confdefs.h
 
   fi
-
-# check for readline 2.2
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <readline/readline.h>
-_ACEOF
-if ac_fn_c_try_cpp "$LINENO"; then :
-  have_readline=yes
-else
-  have_readline=no
-
 fi
-rm -f conftest.err conftest.i conftest.$ac_ext
-if test $have_readline = yes
-then
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <readline/readline.h>
 
-_ACEOF
+if test "$py_cv_lib_readline" = yes; then
-if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  # check for readline 2.2
-  $EGREP "extern int rl_completion_append_character;" >/dev/null 2>&1; then :
+  ac_fn_c_check_decl "$LINENO" "rl_completion_append_character" "ac_cv_have_decl_rl_completion_append_character" "
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
+
+"
+if test "x$ac_cv_have_decl_rl_completion_append_character" = xyes; then :
 
 $as_echo "#define HAVE_RL_COMPLETION_APPEND_CHARACTER 1" >>confdefs.h
 
 fi
-rm -f conftest*
 
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+  ac_fn_c_check_decl "$LINENO" "rl_completion_suppress_append" "ac_cv_have_decl_rl_completion_suppress_append" "
-/* end confdefs.h.  */
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
 # include <readline/readline.h>
+#endif
 
-_ACEOF
+"
-if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+if test "x$ac_cv_have_decl_rl_completion_suppress_append" = xyes; then :
-  $EGREP "extern int rl_completion_suppress_append;" >/dev/null 2>&1; then :
 
 $as_echo "#define HAVE_RL_COMPLETION_SUPPRESS_APPEND 1" >>confdefs.h
 
 fi
-rm -f conftest*
 
-fi
 
   # check for readline 4.0
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_pre_input_hook in -lreadline" >&5
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_rl_pre_input_hook" | $as_tr_sh`
-$as_echo_n "checking for rl_pre_input_hook in -lreadline... " >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_pre_input_hook in -l$LIBREADLINE" >&5
-if ${ac_cv_lib_readline_rl_pre_input_hook+:} false; then :
+$as_echo_n "checking for rl_pre_input_hook in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15728,17 +15750,18 @@ return rl_pre_input_hook ();
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_rl_pre_input_hook=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_rl_pre_input_hook=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_rl_pre_input_hook" >&5
+eval ac_res=\$$as_ac_Lib
-$as_echo "$ac_cv_lib_readline_rl_pre_input_hook" >&6; }
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
-if test "x$ac_cv_lib_readline_rl_pre_input_hook" = xyes; then :
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_PRE_INPUT_HOOK 1" >>confdefs.h
 
@@ -15746,13 +15769,14 @@ fi
 
 
   # also in 4.0
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_completion_display_matches_hook in -lreadline" >&5
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_rl_completion_display_matches_hook" | $as_tr_sh`
-$as_echo_n "checking for rl_completion_display_matches_hook in -lreadline... " >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_completion_display_matches_hook in -l$LIBREADLINE" >&5
-if ${ac_cv_lib_readline_rl_completion_display_matches_hook+:} false; then :
+$as_echo_n "checking for rl_completion_display_matches_hook in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15772,17 +15796,18 @@ return rl_completion_display_matches_hook ();
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_rl_completion_display_matches_hook=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_rl_completion_display_matches_hook=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_rl_completion_display_matches_hook" >&5
+eval ac_res=\$$as_ac_Lib
-$as_echo "$ac_cv_lib_readline_rl_completion_display_matches_hook" >&6; }
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
-if test "x$ac_cv_lib_readline_rl_completion_display_matches_hook" = xyes; then :
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK 1" >>confdefs.h
 
@@ -15790,13 +15815,14 @@ fi
 
 
   # also in 4.0, but not in editline
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_resize_terminal in -lreadline" >&5
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_rl_resize_terminal" | $as_tr_sh`
-$as_echo_n "checking for rl_resize_terminal in -lreadline... " >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_resize_terminal in -l$LIBREADLINE" >&5
-if ${ac_cv_lib_readline_rl_resize_terminal+:} false; then :
+$as_echo_n "checking for rl_resize_terminal in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15816,17 +15842,18 @@ return rl_resize_terminal ();
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_rl_resize_terminal=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_rl_resize_terminal=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_rl_resize_terminal" >&5
+eval ac_res=\$$as_ac_Lib
-$as_echo "$ac_cv_lib_readline_rl_resize_terminal" >&6; }
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
-if test "x$ac_cv_lib_readline_rl_resize_terminal" = xyes; then :
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_RESIZE_TERMINAL 1" >>confdefs.h
 
@@ -15834,13 +15861,14 @@ fi
 
 
   # check for readline 4.2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_completion_matches in -lreadline" >&5
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_rl_completion_matches" | $as_tr_sh`
-$as_echo_n "checking for rl_completion_matches in -lreadline... " >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_completion_matches in -l$LIBREADLINE" >&5
-if ${ac_cv_lib_readline_rl_completion_matches+:} false; then :
+$as_echo_n "checking for rl_completion_matches in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15860,17 +15888,18 @@ return rl_completion_matches ();
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_rl_completion_matches=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_rl_completion_matches=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_rl_completion_matches" >&5
+eval ac_res=\$$as_ac_Lib
-$as_echo "$ac_cv_lib_readline_rl_completion_matches" >&6; }
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
-if test "x$ac_cv_lib_readline_rl_completion_matches" = xyes; then :
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_COMPLETION_MATCHES 1" >>confdefs.h
 
@@ -15878,41 +15907,30 @@ fi
 
 
   # also in readline 4.2
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+  ac_fn_c_check_decl "$LINENO" "rl_catch_signals" "ac_cv_have_decl_rl_catch_signals" "
-/* end confdefs.h.  */
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
 # include <readline/readline.h>
-_ACEOF
+#endif
-if ac_fn_c_try_cpp "$LINENO"; then :
-  have_readline=yes
-else
-  have_readline=no
 
-fi
+"
-rm -f conftest.err conftest.i conftest.$ac_ext
+if test "x$ac_cv_have_decl_rl_catch_signals" = xyes; then :
-if test $have_readline = yes
-then
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <readline/readline.h>
-
-_ACEOF
-if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
-  $EGREP "extern int rl_catch_signals;" >/dev/null 2>&1; then :
 
 $as_echo "#define HAVE_RL_CATCH_SIGNAL 1" >>confdefs.h
 
 fi
-rm -f conftest*
 
-fi
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for append_history in -lreadline" >&5
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_append_history" | $as_tr_sh`
-$as_echo_n "checking for append_history in -lreadline... " >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for append_history in -l$LIBREADLINE" >&5
-if ${ac_cv_lib_readline_append_history+:} false; then :
+$as_echo_n "checking for append_history in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15932,22 +15950,24 @@ return append_history ();
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_append_history=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_append_history=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_append_history" >&5
+eval ac_res=\$$as_ac_Lib
-$as_echo "$ac_cv_lib_readline_append_history" >&6; }
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
-if test "x$ac_cv_lib_readline_append_history" = xyes; then :
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_APPEND_HISTORY 1" >>confdefs.h
 
 fi
 
+fi
 
 # End of readline checks: restore LIBS
 LIBS=$LIBS_no_readline

configure.ac

@@ -4891,20 +4891,41 @@ then
   [Define this if you have flockfile(), getc_unlocked(), and funlockfile()])
 fi
 
+AC_ARG_WITH([readline],
+  [AS_HELP_STRING([--with(out)-readline@<:@=editline@:>@],
+    [use Editline for backend or disable readline module])],
+    [],
+    [with_readline=yes])
+
 # check where readline lives
+py_cv_lib_readline=no
 # save the value of LIBS so we don't actually link Python with readline
 LIBS_no_readline=$LIBS
 
+if test "$with_readline" != no; then
+  case "$with_readline" in
+  editline|edit)
+    LIBREADLINE=edit
+    AC_DEFINE(WITH_EDITLINE, 1,
+      [Define to build the readline module against Editline.])
+    ;;
+  yes|readline)
+    LIBREADLINE=readline
+    ;;
+  *)
+    AC_MSG_ERROR([proper usage is --with(out)-readline@<:@=editline@:>@])
+    ;;
+  esac
+
   # On some systems we need to link readline to a termcap compatible
   # library.  NOTE: Keep the precedence of listed libraries synchronised
   # with setup.py.
-py_cv_lib_readline=no
   AC_MSG_CHECKING([how to link readline libs])
   for py_libtermcap in "" tinfo ncursesw ncurses curses termcap; do
     if test -z "$py_libtermcap"; then
-    READLINE_LIBS="-lreadline"
+      READLINE_LIBS="-l$LIBREADLINE"
     else
-    READLINE_LIBS="-lreadline -l$py_libtermcap"
+      READLINE_LIBS="-l$LIBREADLINE -l$py_libtermcap"
     fi
     LIBS="$READLINE_LIBS $LIBS_no_readline"
     AC_LINK_IFELSE(
@@ -4914,69 +4935,80 @@ for py_libtermcap in "" tinfo ncursesw ncurses curses termcap; do
       break
     fi
   done
-# Uncomment this line if you want to use READINE_LIBS in Makefile or scripts
+
+  # Uncomment this line if you want to use READLINE_LIBS in Makefile or scripts
   #AC_SUBST([READLINE_LIBS])
   if test $py_cv_lib_readline = no; then
     AC_MSG_RESULT([none])
   else
     AC_MSG_RESULT([$READLINE_LIBS])
     AC_DEFINE(HAVE_LIBREADLINE, 1,
-    [Define if you have the readline library (-lreadline).])
+      [Define to build the readline module.])
+  fi
 fi
 
+if test "$py_cv_lib_readline" = yes; then
   # check for readline 2.2
-AC_PREPROC_IFELSE([AC_LANG_SOURCE([[#include <readline/readline.h>]])],
+  AC_CHECK_DECL(rl_completion_append_character,
-  [have_readline=yes],
-  [have_readline=no]
-)
-if test $have_readline = yes
-then
-  AC_EGREP_HEADER([extern int rl_completion_append_character;],
-  [readline/readline.h],
     AC_DEFINE(HAVE_RL_COMPLETION_APPEND_CHARACTER, 1,
-  [Define if you have readline 2.2]), )
+      [Define if you have readline 2.2]),,
-  AC_EGREP_HEADER([extern int rl_completion_suppress_append;],
+    [
-  [readline/readline.h],
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
+    ])
+  AC_CHECK_DECL(rl_completion_suppress_append,
     AC_DEFINE(HAVE_RL_COMPLETION_SUPPRESS_APPEND, 1,
-  [Define if you have rl_completion_suppress_append]), )
+      [Define if you have rl_completion_suppress_append]),,
-fi
+    [
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
+    ])
 
   # check for readline 4.0
-AC_CHECK_LIB(readline, rl_pre_input_hook,
+  AC_CHECK_LIB($LIBREADLINE, rl_pre_input_hook,
     AC_DEFINE(HAVE_RL_PRE_INPUT_HOOK, 1,
       [Define if you have readline 4.0]),,$READLINE_LIBS)
 
   # also in 4.0
-AC_CHECK_LIB(readline, rl_completion_display_matches_hook,
+  AC_CHECK_LIB($LIBREADLINE, rl_completion_display_matches_hook,
     AC_DEFINE(HAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK, 1,
       [Define if you have readline 4.0]),,$READLINE_LIBS)
 
   # also in 4.0, but not in editline
-AC_CHECK_LIB(readline, rl_resize_terminal,
+  AC_CHECK_LIB($LIBREADLINE, rl_resize_terminal,
     AC_DEFINE(HAVE_RL_RESIZE_TERMINAL, 1,
       [Define if you have readline 4.0]),,$READLINE_LIBS)
 
   # check for readline 4.2
-AC_CHECK_LIB(readline, rl_completion_matches,
+  AC_CHECK_LIB($LIBREADLINE, rl_completion_matches,
     AC_DEFINE(HAVE_RL_COMPLETION_MATCHES, 1,
       [Define if you have readline 4.2]),,$READLINE_LIBS)
 
   # also in readline 4.2
-AC_PREPROC_IFELSE([AC_LANG_SOURCE([[#include <readline/readline.h>]])],
+  AC_CHECK_DECL(rl_catch_signals,
-  [have_readline=yes],
-  [have_readline=no]
-)
-if test $have_readline = yes
-then
-  AC_EGREP_HEADER([extern int rl_catch_signals;],
-  [readline/readline.h],
     AC_DEFINE(HAVE_RL_CATCH_SIGNAL, 1,
-  [Define if you can turn off readline's signal handling.]), )
+      [Define if you can turn off readline's signal handling.]),,
-fi
+    [
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
+    ])
 
-AC_CHECK_LIB(readline, append_history,
+  AC_CHECK_LIB($LIBREADLINE, append_history,
     AC_DEFINE(HAVE_RL_APPEND_HISTORY, 1,
       [Define if readline supports append_history]),,$READLINE_LIBS)
+fi
 
 # End of readline checks: restore LIBS
 LIBS=$LIBS_no_readline

pyconfig.h.in

@@ -610,7 +610,7 @@
 /* Define to 1 if you have the <libintl.h> header file. */
 #undef HAVE_LIBINTL_H
 
-/* Define if you have the readline library (-lreadline). */
+/* Define to build the readline module. */
 #undef HAVE_LIBREADLINE
 
 /* Define to 1 if you have the `resolv' library (-lresolv). */
@@ -1554,6 +1554,9 @@
    Dyld is necessary to support frameworks. */
 #undef WITH_DYLD
 
+/* Define to build the readline module against Editline. */
+#undef WITH_EDITLINE
+
 /* Define to 1 if libintl is needed for locale functions. */
 #undef WITH_LIBINTL
 

setup.py

@@ -1022,7 +1022,6 @@ class PyBuildExt(build_ext):
 
     def detect_readline_curses(self):
         # readline
-        do_readline = self.compiler.find_library_file(self.lib_dirs, 'readline')
         readline_termcap_library = ""
         curses_library = ""
         # Cannot use os.popen here in py3k.
@@ -1030,7 +1029,13 @@ class PyBuildExt(build_ext):
         if not os.path.exists(self.build_temp):
             os.makedirs(self.build_temp)
         # Determine if readline is already linked against curses or tinfo.
-        if do_readline:
+        if sysconfig.get_config_var('HAVE_LIBREADLINE'):
+            if sysconfig.get_config_var('WITH_EDITLINE'):
+                readline_lib = 'edit'
+            else:
+                readline_lib = 'readline'
+            do_readline = self.compiler.find_library_file(self.lib_dirs,
+                readline_lib)
             if CROSS_COMPILING:
                 ret = run_command("%s -d %s | grep '(NEEDED)' > %s"
                                 % (sysconfig.get_config_var('READELF'),
@@ -1053,6 +1058,8 @@ class PyBuildExt(build_ext):
                             break
             if os.path.exists(tmpfile):
                 os.unlink(tmpfile)
+        else:
+            do_readline = False
         # Issue 7384: If readline is already linked against curses,
         # use the same library for the readline and curses modules.
         if 'curses' in readline_termcap_library:
@@ -1092,7 +1099,7 @@ class PyBuildExt(build_ext):
             else:
                 readline_extra_link_args = ()
 
-            readline_libs = ['readline']
+            readline_libs = [readline_lib]
             if readline_termcap_library:
                 pass # Issue 7384: Already linked against curses or tinfo.
             elif curses_library: