Add compile option to disable error logging

If you have an application stderr shall not be used by libsocketcan
you can disable all error logging by defining DISABLE_ERROR_LOG.

Signed-off-by: Leo Ruan <tingquan.ruan@cn.bosch.com>
Signed-off-by: Mark Jonas <mark.jonas@de.bosch.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

src/libsocketcan.c

@@ -36,6 +36,12 @@
 
 #include <libsocketcan.h>
 
+/* Define DISABLE_ERROR_LOG to disable printing of error messages to stderr. */
+#ifdef DISABLE_ERROR_LOG
+#define perror(x)
+#define fprintf(...)
+#endif
+
 #define parse_rtattr_nested(tb, max, rta) \
 	(parse_rtattr((tb), (max), RTA_DATA(rta), RTA_PAYLOAD(rta)))