Add multi_logger.odin; Fix os_windows.odin

core/log/multi_logger.odin

@@ -0,0 +1,26 @@
+package log
+
+
+Multi_Logger_Data :: struct {
+	loggers: []Logger,
+}
+
+create_multi_logger :: proc(logs: ..Logger) -> Logger {
+	data := new(Multi_Logger_Data);
+	data.loggers = make([]Logger, len(logs));
+	copy(data.loggers, logs);
+	return Logger{multi_logger_proc, data, Level.Debug, nil};
+}
+
+destroy_multi_logger :: proc(log : ^Logger) {
+	free(log.data);
+	log^ = nil_logger();
+}
+
+multi_logger_proc :: proc(logger_data: rawptr, level: Level, text: string,
+                          options: Options, location := #caller_location) {
+	data := cast(^Multi_Logger_Data)logger_data;
+	for log in data.loggers {
+		log.procedure(log.data, level, text, log.options, location);
+	}
+}

core/os/os_windows.odin

@@ -76,13 +76,13 @@ open :: proc(path: string, mode: int = O_RDONLY, perm: int = 0) -> (Handle, Errn
 	case O_RDWR:   access = win32.FILE_GENERIC_READ | win32.FILE_GENERIC_WRITE;
 	}
 
-	if mode&O_CREATE != 0 {
-		access |= win32.FILE_GENERIC_WRITE;
-	}
 	if mode&O_APPEND != 0 {
 		access &~= win32.FILE_GENERIC_WRITE;
 		access |=  win32.FILE_APPEND_DATA;
 	}
+	if mode&O_CREATE != 0 {
+		access |= win32.FILE_GENERIC_WRITE;
+	}
 
 	share_mode := u32(win32.FILE_SHARE_READ|win32.FILE_SHARE_WRITE);
 	sa: ^win32.Security_Attributes = nil;