Get ruby-2.0.0 to build on Ubuntu 14.04

ruby-2.0.0.diff

Used this to build ruby-2.0.0 on Ubuntu 14.04. The command was:

    rbenv install --patch 2.0.0-p353 < ruby-2.0.0.diff

Ref: https://github.com/sstephenson/ruby-build/issues/526#issuecomment-37932244

diff -ur ext/readline/readline.c ext/readline/readline.c
--- ext/readline/readline.c    2014-03-18 13:53:31.866359527 +0100
+++ ext/readline/readline.c   2014-03-18 13:56:26.390247250 +0100
@@ -1883,7 +1883,7 @@

     rl_attempted_completion_function = readline_attempted_completion_function;
 #if defined(HAVE_RL_PRE_INPUT_HOOK)
-    rl_pre_input_hook = (Function *)readline_pre_input_hook;
+    rl_pre_input_hook = (rl_hook_func_t *)readline_pre_input_hook;
 #endif
 #ifdef HAVE_RL_CATCH_SIGNALS
     rl_catch_signals = 0;