inet: resolve some compile and runtime warnings

- ping(1) triggers warnings about unimplemented exceptions for select;
  even if there could be a useful implementation (which is doubtful),
  the warnings are not helping anyone right now;
- the clock_t data type has changed.

Change-Id: Ie5b1383e7657e8501f63bb4b9d255c6502567a15

minix/net/inet/clock.c

@@ -54,7 +54,7 @@ clock_t tim;
 	}
 	else if (!curr_time)
 	{
-		DBLOCK(0x20, printf("set_time: new time %u < prev_time %u\n",
+		DBLOCK(0x20, printf("set_time: new time %lu < prev_time %lu\n",
 			tim, prev_time));
 	}
 }

minix/net/inet/generic/eth.c

@@ -680,7 +680,7 @@ unsigned operations;
 	}
 	if (operations & SR_SELECT_EXCEPTION)
 	{
-		printf("eth_select: not implemented for exceptions\n");
+		/* Nothing */
 	}
 	return resops;
 }

minix/net/inet/generic/ip.c

@@ -206,7 +206,7 @@ unsigned operations;
 	}
 	if (operations & SR_SELECT_EXCEPTION)
 	{
-		printf("ip_select: not implemented for exceptions\n");
+		/* Nothing */
 	}
 	return resops;
 }

minix/net/inet/generic/udp.c

@@ -316,12 +316,10 @@ unsigned operations;
 		/* Should handle special case when the interface is down */
 		resops |= SR_SELECT_WRITE;
 	}
-#if DEBUG == 1
 	if (operations & SR_SELECT_EXCEPTION)
 	{
-		printf("udp_select: not implemented for exceptions\n");
+		/* Nothing */
 	}
-#endif
 	return resops;
 }