Quieten a few compiler warnings.

CYGWIN.md

@@ -24,19 +24,15 @@ and enter valid DNS server addresses, e.g. `8.8.8.8`.
   * `flex` for compiling `libconfig`
   * `bison` for compiling `libconfig` 
 
-* Download, configure, compile and install `libconfig`.
-
-For this, if your home directory name has a space in it, which happens by default with Cygwin, you should
-temporarily rename it to a single word, e.g. `Mike Brady` -> `mike`. This is to allow the `make install` script to work properly.
+* Download, configure, compile and install `libconfig`:
 ```
-$ wget http://www.hyperrealm.com/libconfig/libconfig-1.5.tar.gz
-$ tar -xvzf  libconfig-1.5.tar.gz
-$ cd libconfig-1.5
+$ git clone https://github.com/hyperrealm/libconfig.git
+$ autoreconf -fi
 $ ./configure
 $ make
 $ make install
 $ cd ..
-``` 
+```
 * Next, download, configure and compile Shairport Sync:
 ```
 $ git clone https://github.com/mikebrady/shairport-sync.git

player.c

@@ -1556,7 +1556,7 @@ static void *player_thread_func(void *arg) {
   int at_least_one_frame_seen = 0;
   int64_t tsum_of_sync_errors, tsum_of_corrections, tsum_of_insertions_and_deletions,
       tsum_of_drifts;
-  int64_t previous_sync_error, previous_correction;
+  int64_t previous_sync_error = 0, previous_correction = 0;
   int64_t minimum_dac_queue_size = INT64_MAX;
   int32_t minimum_buffer_occupancy = INT32_MAX;
   int32_t maximum_buffer_occupancy = INT32_MIN;
@@ -2516,7 +2516,7 @@ void player_volume_without_notification(double airplay_volume, rtsp_conn_info *c
       }
     }
   */
-  double hardware_attenuation, software_attenuation = 0.0;
+  double hardware_attenuation = 0.0, software_attenuation = 0.0;
   double scaled_attenuation = hw_min_db + sw_min_db;
 
   // now, we can map the input to the desired output volume

rtp.c

@@ -709,7 +709,7 @@ static uint16_t bind_port(int ip_family, const char *self_ip_address, uint32_t s
                           int *sock) {
   // look for a port in the range, if any was specified.
   uint16_t desired_port = config.udp_port_base;
-  int ret;
+  int ret = 0;
 
   int local_socket = socket(ip_family, SOCK_DGRAM, IPPROTO_UDP);
   if (local_socket == -1)