Fix errors in error cases

Leak FDs in error exits, seg faults if RIG missing.
Found by `gcc -fanalyzer`

rigs/yaesu/ft100.c

@@ -971,8 +971,7 @@ int ft100_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
 {
 
     int ret;
-    int split = CACHE(rig)->split;
-    int ptt = CACHE(rig)->ptt;
+    int split, ptt;
 
     FT100_METER_INFO ft100_meter;
 
@@ -980,6 +979,9 @@ int ft100_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
 
     if (!val) { return -RIG_EINVAL; }
 
+    split = CACHE(rig)->split;
+    ptt = CACHE(rig)->ptt;
+
     rig_debug(RIG_DEBUG_VERBOSE, "%s: %s\n", __func__, rig_strlevel(level));
 
     // if in split have to switch to VFOB to read power and back to VFOA

rotators/gs232a/gs232.c

@@ -198,7 +198,7 @@ gs232_rot_set_position(ROT *rot, azimuth_t az, elevation_t el)
 static int
 gs232_rot_get_position(ROT *rot, azimuth_t *az, elevation_t *el)
 {
-    char posbuf[32];
+    char posbuf[BUFSZ];
     // these really shouldn't be static but it's fixing faulty firmware -- see below
     static int expected = 12;
     static int expected_flag = 0;

src/network.c

@@ -1348,7 +1348,7 @@ int is_wireless()
 static void *multicast_receiver(void *arg)
 {
     char data[4096];
-    char ip4[INET6_ADDRSTRLEN];
+    char ip4[INET6_ADDRSTRLEN] = "";
 
     struct multicast_receiver_args_s *args = (struct multicast_receiver_args_s *)
             arg;

src/settings.c

@@ -1266,6 +1266,8 @@ HAMLIB_EXPORT(int) rig_settings_load_all(char *settings_file)
         }
     }
 
+    fclose(fp);
+
     return RIG_OK;
 }