This reverts commit c97aa848.

* feat: remove using namespace mediakit in header files.

(cherry picked from commit d44aeb339a8a0e1f0455be82b21fe4b1b536299f)

* feat: remove using namespace mediakit in FFmpegSource.h

* feat: remove using namespace mediakit in RtpExt.h

* feat: remove using namespace mediakit in header files.

* feat: remove using namespace std in header files.

* feat: remove using namespace std in header files when zltoolkit remove std in header

* 补充命名空间

* 整理命名空间

* 整理命名空间2

* 修复macos ci

* 修复编译问题

* 修复编译问题2

* 修复编译问题3

Co-authored-by: Johnny <hellojinqiang@gmail.com>
Co-authored-by: Xiaofeng Wang <wasphin@gmail.com>

* 增加检测atomic源文件

* 支持树莓派编译，自动检测atomic链接库

* 精简cmake操作

* 当调用mk_media_source_close(ptr, 1);时，主动注销流

主动调用上述函数时，期望不再等待RtmpSession.cpp:49处getPoller()->doDelayTask(continue_push_ms, [push_src]() { return 0; });捕获的指针，等待析构时反注册，而是立即反注册。

* `MediaSource::close`逻辑执行成功后执行`unregist`

同时修复websocket客户端判断alive返回false的bug

This reverts commit 8937d9ea.