Add q() macro that checks quiet flag.

cmd.c

 	}
 
 	if (!v) {
-		if (!quiet) {
-			fprintf(stderr, "WARNING: Videohub sent unknown command!\n");
-			fprintf(stderr, "         Please report this command to author's email: georgi@unixsol.org\n");
-			fprintf(stderr, "         You may use -q or --quiet to suppress the message.\n");
-			fprintf(stderr, "---------8<-----------8<----------- cut here ---------8<------------8<---------\n");
-			fprintf(stderr, "%s\n", cmd);
-			fprintf(stderr, "---------8<-----------8<----------- cut here ---------8<------------8<---------\n");
-		}
+		q("WARNING: Videohub sent unknown command!\n");
+		q("         Please report this command to author's email: georgi@unixsol.org\n");
+		q("         You may use -q or --quiet to suppress the message.\n");
+		q("---------8<-----------8<----------- cut here ---------8<------------8<---------\n");
+		q("%s\n", cmd);
+		q("---------8<-----------8<----------- cut here ---------8<------------8<---------\n");
 		return false;
 	}
 

data.h

 			printf("debug: " fmt, ## arguments); \
 	} while(0)
 
+#define q(fmt, arguments...) \
+	do { \
+		if (!quiet) \
+			fprintf(stderr, fmt, ## arguments); \
+	} while(0)
+
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 #define MIN(a,b) (((a) < (b)) ? (a) : (b))
 #define UNUSED(x) UNUSED_ ## x __attribute__((unused))