Fix initialization in test/iodelay.cpp

jack_latency_range_t is

struct _jack_latency_range {
    jack_nframes_t min;
    jack_nframes_t max;
};

and jack_nframes_t is

typedef uint32_t        jack_nframes_t;

so it's unsigned. Initialising it with -1 is invalid (at least in C++14). We cannot use {0, 0}, because latency_cb has

   jack_latency_range_t range;
   range.min = range.max = 0;
   if ((range.min != capture_latency.min) || (range.max !=
       capture_latency.max)) {
       capture_latency = range;
   }

so we must not have {0, 0}, otherwise the condition would never be true.

Using UINT32_MAX should be equivalent to the previous -1.

tests/iodelay.cpp

@@ -20,6 +20,7 @@
 
 #include <stdlib.h>
 #include <stdio.h>
+#include <stdint.h>
 #include <math.h>
 #include <unistd.h>
 #include <jack/jack.h>
@@ -167,8 +168,8 @@ static jack_client_t  *jack_handle;
 static jack_port_t    *jack_capt;
 static jack_port_t    *jack_play;
 
-jack_latency_range_t   capture_latency = {-1, -1};
-jack_latency_range_t   playback_latency = {-1, -1};
+jack_latency_range_t   capture_latency = {UINT32_MAX, UINT32_MAX};
+jack_latency_range_t   playback_latency = {UINT32_MAX, UINT32_MAX};
 
 void
 latency_cb (jack_latency_callback_mode_t mode, void *arg)
@@ -266,4 +267,4 @@ int main (int ac, char *av [])
     return 0;
 }
 
-// --------------------------------------------------------------------------------
+// --------------------------------------------------------------------------------