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>

src/bacnet/basic/service/h_ucov.c

@@ -36,15 +36,11 @@
 #include "bacnet/cov.h"
 #include "bacnet/bactext.h"
 #include "bacnet/basic/services.h"
+#include "bacnet/basic/sys/debug.h"
 #include "bacnet/basic/tsm/tsm.h"
 
 /** @file h_ucov.c  Handles Unconfirmed COV Notifications. */
-#if PRINT_ENABLED
-#include <stdio.h>
-#define PRINTF(...) fprintf(stderr, __VA_ARGS__)
-#else
-#define PRINTF(...)
-#endif
+#define PRINTF debug_perror
 
 #ifndef MAX_COV_PROPERTIES
 #define MAX_COV_PROPERTIES 2