Bugfix/code clean using gcc warnings (#371)

* Enable extra GCC warnings to discover subtle bugs

* convert c++ comments to c comments

* cleanup pedantic compiler warnings

* Compile apps with GNU89 GNU99 GNU11 and GNU17

Co-authored-by: Steve Karg <skarg@users.sourceforge.net>

ports/linux/bip-init.c

@@ -204,6 +204,7 @@ void bip_get_broadcast_address(BACNET_ADDRESS *dest)
 bool bip_set_addr(BACNET_IP_ADDRESS *addr)
 {
     /* not something we do within this driver */
+    (void)addr;
     return false;
 }
 
@@ -230,6 +231,7 @@ bool bip_get_addr(BACNET_IP_ADDRESS *addr)
 bool bip_set_broadcast_addr(BACNET_IP_ADDRESS *addr)
 {
     /* not something we do within this driver */
+    (void)addr;
     return false;
 }
 
@@ -255,6 +257,7 @@ bool bip_get_broadcast_addr(BACNET_IP_ADDRESS *addr)
 bool bip_set_subnet_prefix(uint8_t prefix)
 {
     /* not something we do within this driver */
+    (void)prefix;
     return false;
 }
 
@@ -336,7 +339,7 @@ uint16_t bip_receive(
     int max = 0;
     struct timeval select_timeout;
     struct sockaddr_in sin = { 0 };
-    BACNET_IP_ADDRESS addr = { { 0 } };
+    BACNET_IP_ADDRESS addr = { 0 };
     socklen_t sin_len = sizeof(sin);
     int received_bytes = 0;
     int offset = 0;
@@ -657,6 +660,8 @@ static void parseRoutes(struct nlmsghdr *nlHdr, struct route_info *rtInfo)
             case RTA_DST:
                 rtInfo->dstAddr = *(u_int *)RTA_DATA(rtAttr);
                 break;
+            default:
+                break;
         }
     }
 }