input: switch InputOption to use XF86OptionRec storage.

Use the same struct for both InputOption and XF86OptionRec so we don't need
to convert to and fro the two in the config backends.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Dan Nicholson <dbn.lists@gmail.com>
Reviewed-by: Daniel Stone <daniel@fooishbar.org>

include/inputstr.h

@@ -621,11 +621,4 @@ static inline WindowPtr DeepestSpriteWin(SpritePtr sprite)
     return sprite->spriteTrace[sprite->spriteTraceGood - 1];
 }
 
-struct _InputOption {
-    char                *key;
-    char                *value;
-    struct _InputOption *next;
-};
-
-
 #endif /* INPUTSTRUCT_H */