tools: acrn-crashlog: framework of acrn-crashlog

This is the first patch of acrn-crashlog.

This patch initializes the framework of acrn-crashlog: acrnprobe,
common, data, and usercrash. And it initializes the Makefile for
each part.

Signed-off-by: Liu Xinwu <xinwu.liu@intel.com>
Signed-off-by: CHEN Gang <gang.c.chen@intel.com>
Reviewed-by: Zhang Yanmin <yanmin.zhang@intel.com>
Reviewed-by: Liu Chuansheng <chuansheng.liu@intel.com>
Reviewed-by: Zhao Yakui <yakui.zhao@intel.com>
Reviewed-by: Geoffroy Van Cutsem <geoffroy.vancutsem@intel.com>
Acked-by: Eddie Dong <Eddie.dong@intel.com>

tools/acrn-crashlog/usercrash/server.c

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) <2018> Intel Corporation
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/**
+ * Usercrash works as C/S model: usercrash_s works as usercrash server, which
+ * is to handle events from client in endless loop. Once server receives events
+ * from client, it will create usercrash_0x file under /var/log/usercrashes/
+ * and send file fd to client. Then server will wait for client filling the
+ * event info completely to the crash file. After client's work has been done,
+ * server will be responsiable to free the crash node and process other events.
+ */
+
+int main(void)
+{
+	//TO BE DONE
+	//This empty function is to satisfy the dependency of Makefile.
+	//This is the entry of usercrash_s, the implementation will be filled
+	//by following patches.
+	return 0;
+}