commandError() cleanups, fixup gcc checks

stripped binary size reduced by 9k on my machine from making
commandError a function.  We'll print out error messages slightly
slower before, but the smaller binary is more than worth it.

git-svn-id: https://svn.musicpd.org/mpd/trunk@4488 09075e82-0dd4-0310-85a5-a0d7c8717e4f

src/command.h

@@ -48,18 +48,6 @@ void finishCommands();
 
 #define commandSuccess(fd)              fdprintf(fd, "OK\n")
 
-#define commandError(fd, error, format, ... ) do \
-	{\
-		if (current_command) { \
-			fdprintf(fd, "ACK [%i@%i] {%s} " format "\n", \
-					(int)error, command_listNum, \
-					current_command, __VA_ARGS__); \
-			current_command = NULL; \
-		} \
-		else { \
-			fdprintf(STDERR_FILENO, "ACK [%i@%i] " format "\n", \
-					(int)error, command_listNum, \
-					__VA_ARGS__); \
-		} \
-	} while (0)
+mpd_fprintf_ void commandError(int fd, int error, const char *fmt, ...);
+
 #endif