Disable "register" variable name

Fixes https://github.com/jackaudio/jack1/issues/84

types.h

@@ -386,7 +386,7 @@ typedef int  (*JackSampleRateCallback)(jack_nframes_t nframes, void *arg);
  * @param register non-zero if the port is being registered,
  *                     zero if the port is being unregistered
  */ 
-typedef void (*JackPortRegistrationCallback)(jack_port_id_t port, int register, void *arg);
+typedef void (*JackPortRegistrationCallback)(jack_port_id_t port, int /* register */, void *arg);
 
 /**
  * Prototype for the client supplied function that is called 
@@ -408,7 +408,7 @@ typedef void (*JackPortRenameCallback)(jack_port_id_t port, const char* old_name
  *                     zero if the client is being unregistered
  * @param arg pointer to a client supplied data
  */ 
-typedef void (*JackClientRegistrationCallback)(const char* name, int register, void *arg);
+typedef void (*JackClientRegistrationCallback)(const char* name, int /* register */, void *arg);
 
 /**
  * Prototype for the client supplied function that is called