daemon: use full buffered mode for stderr

Windows doesn't support line buffered mode for file
streams, so let's just use full buffered mode with
a big buffer ("4096 should be enough for everyone")
and add explicit flushing.

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

daemon.c

@@ -67,12 +67,14 @@ static void logreport(int priority, const char *err, va_list params)
 		syslog(priority, "%s", buf);
 	} else {
 		/*
-		 * Since stderr is set to linebuffered mode, the
+		 * Since stderr is set to buffered mode, the
 		 * logging of different processes will not overlap
+		 * unless they overflow the (rather big) buffers.
 		 */
 		fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
 		vfprintf(stderr, err, params);
 		fputc('\n', stderr);
+		fflush(stderr);
 	}
 }
 
@@ -1117,7 +1119,7 @@ int main(int argc, char **argv)
 		set_die_routine(daemon_die);
 	} else
 		/* avoid splitting a message in the middle */
-		setvbuf(stderr, NULL, _IOLBF, 0);
+		setvbuf(stderr, NULL, _IOFBF, 4096);
 
 	if (inetd_mode && (group_name || user_name))
 		die("--user and --group are incompatible with --inetd");