uint64 compaliable with gcc and vc

modules/uhd/uhd_usrp_io/uhd_io.cpp

@@ -348,7 +348,7 @@ int do_iio(const cmdlineParser & args)
 						UHD_DO(uhd_rx_metadata_has_time_spec(rx_meta, &hasTm));
 						if (hasTm)
 						{
-							long int rx_time_sec;
+							int64_t rx_time_sec;
 							double rx_time_frag;
 							uhd_rx_metadata_time_spec(rx_meta,
 													  &rx_time_sec, & rx_time_frag);
@@ -390,7 +390,7 @@ int do_iio(const cmdlineParser & args)
 									(unsigned char *) &buf_rx_list[stdout_pos % sz_buffer_rx].tmstmp );
 					}
 					for (int ch = 0;ch<rx_channel_count;++ch)
-					{						
+					{
 						if (i_wav_rx[ch]>0)
 						{
 							tag_sig_block & dta = buf_rx_list[stdout_pos % sz_buffer_rx];