readline5: recover, as it was still used

Partial revert of 30fef8a3cffbc1.
I probably confused that with unused readline62.

pkgs/development/libraries/readline/readline5.nix

···
+{ stdenv, fetchurl, ncurses }:
+
+stdenv.mkDerivation {
+  name = "readline-5.2";
+
+  src = fetchurl {
+    url = mirror://gnu/readline/readline-5.2.tar.gz;
+    sha256 = "0icz4hqqq8mlkwrpczyaha94kns0am9z0mh3a2913kg2msb8vs0j";
+  };
+
+  propagatedBuildInputs = [ncurses];
+
+  patches = stdenv.lib.optional stdenv.isDarwin ./shobj-darwin.patch;
+}
+

pkgs/development/libraries/readline/shobj-darwin.patch

···
+--- a/support/shobj-conf.orig	2006-04-11 06:15:43.000000000 -0700
++++ b/support/shobj-conf	2007-11-08 01:15:43.000000000 -0800
+@@ -171,7 +171,7 @@
+ 	SHLIB_LIBSUFF='dylib'
+ 
+ 	case "${host_os}" in
+-	darwin[78]*)	SHOBJ_LDFLAGS=''
++	darwin[789]*)	SHOBJ_LDFLAGS=''
+ 			SHLIB_XLDFLAGS='-dynamiclib -arch_only `/usr/bin/arch` -install_name $(libdir)/$@ -current_version $(SHLIB_MAJOR)$(SHLIB_MINOR) -compatibility_version $(SHLIB_MAJOR) -v'
+ 			;;
+ 	*)		SHOBJ_LDFLAGS='-dynamic'

pkgs/top-level/all-packages.nix

···
   readline = readline6;
   readline6 = readline63;
 
+  readline5 = callPackage ../development/libraries/readline/readline5.nix { };
+
   readline62 = callPackage ../development/libraries/readline/readline6.nix { };
 
   readline63 = callPackage ../development/libraries/readline/readline6.3.nix { };