[ruby/reline] Add original C function declarations comment for each function

https://github.com/ruby/reline/commit/9a25ee9f12

lib/reline/terminfo.rb

@@ -39,12 +39,13 @@ module Reline::Terminfo
   @setupterm = Fiddle::Function.new(curses_dl['setupterm'], [Fiddle::TYPE_VOIDP, Fiddle::TYPE_INT, Fiddle::TYPE_VOIDP], Fiddle::TYPE_INT)
   #extern 'char *tigetstr(char *capname)'
   @tigetstr = Fiddle::Function.new(curses_dl['tigetstr'], [Fiddle::TYPE_VOIDP], Fiddle::TYPE_VOIDP)
-  #extern 'char *tiparm(const char *str, ...)'
-  @tiparm = begin
-    Fiddle::Function.new(curses_dl['tiparm'], [Fiddle::TYPE_VOIDP, Fiddle::TYPE_VARIADIC], Fiddle::TYPE_VOIDP)
-  rescue
+  begin
+    #extern 'char *tiparm(const char *str, ...)'
+    @tiparm = Fiddle::Function.new(curses_dl['tiparm'], [Fiddle::TYPE_VOIDP, Fiddle::TYPE_VARIADIC], Fiddle::TYPE_VOIDP)
+  rescue Fiddle::DLError
     # OpenBSD lacks tiparm
-    Fiddle::Function.new(curses_dl['tparm'], [Fiddle::TYPE_VOIDP, Fiddle::TYPE_VARIADIC], Fiddle::TYPE_VOIDP)
+    #extern 'char *tparm(const char *str, ...)'
+    @tiparm = Fiddle::Function.new(curses_dl['tparm'], [Fiddle::TYPE_VOIDP, Fiddle::TYPE_VARIADIC], Fiddle::TYPE_VOIDP)
   end
   # TODO: add int tigetflag(char *capname) and int tigetnum(char *capname)