- Fix build with readline 6.3 from ports

the patch was obtained from upstream (issue #20374)
- Add missing USES=readline

PR:		ports/187174
Reported by:	O. Hartmann
Reviewed by:	koobs
Obtained from:	python

lang/python27/Makefile

@@ -22,6 +22,7 @@ MAKE_ENV=		VPATH="${PYTHON_WRKSRC}"
 
 INSTALL_TARGET=	altinstall
 
+USES=		readline
 USE_LDCONFIG=	yes
 USE_PYTHON=	yes
 USE_XZ=		yes

lang/python27/files/patch-issue20374

@@ -0,0 +1,55 @@
+# Description: fix readline.so build with readline 6.3
+# Patch obtained from upstream, issue #20374
+# http://bugs.python.org/issue20374
+# PR: ports/187174
+
+--- ./Modules/readline.c.orig	2013-11-10 07:36:41.000000000 +0000
++++ ./Modules/readline.c	2014-03-01 12:40:44.000000000 +0000
+@@ -750,14 +750,22 @@
+ }
+ 
+ static int
++#if defined(_RL_FUNCTION_TYPEDEF)
+ on_startup_hook(void)
++#else
++on_startup_hook()
++#endif
+ {
+     return on_hook(startup_hook);
+ }
+ 
+ #ifdef HAVE_RL_PRE_INPUT_HOOK
+ static int
++#if defined(_RL_FUNCTION_TYPEDEF)
+ on_pre_input_hook(void)
++#else
++on_pre_input_hook()
++#endif
+ {
+     return on_hook(pre_input_hook);
+ }
+@@ -852,7 +860,7 @@
+  * before calling the normal completer */
+ 
+ static char **
+-flex_complete(char *text, int start, int end)
++flex_complete(const char *text, int start, int end)
+ {
+ #ifdef HAVE_RL_COMPLETION_APPEND_CHARACTER
+     rl_completion_append_character ='\0';
+@@ -911,12 +919,12 @@
+     rl_bind_key_in_map ('\t', rl_complete, emacs_meta_keymap);
+     rl_bind_key_in_map ('\033', rl_complete, emacs_meta_keymap);
+     /* Set our hook functions */
+-    rl_startup_hook = (Function *)on_startup_hook;
++    rl_startup_hook = on_startup_hook;
+ #ifdef HAVE_RL_PRE_INPUT_HOOK
+-    rl_pre_input_hook = (Function *)on_pre_input_hook;
++    rl_pre_input_hook = on_pre_input_hook;
+ #endif
+     /* Set our completion function */
+-    rl_attempted_completion_function = (CPPFunction *)flex_complete;
++    rl_attempted_completion_function = flex_complete;
+     /* Set Python word break characters */
+     completer_word_break_characters =
+         rl_completer_word_break_characters =