报错： Error: Multiple commands produce
xcode更新描述：
1、Build System
2、Again, Xcode 10 uses a new build system. The new build system provides improved reliability and build performance, and it catches project configuration problems that the legacy build system does not.
3、The legacy build system is still available in Xcode 10. To use the legacy build system, select it in the File > Project/Workspace Settings sheet. Projects configured to use the legacy build system will display an orange hammer icon in the Activity View.
Xcode10使用了一个新创建系统，比之前的提供更好的可靠性与创建性能，而且可以获取项目配置问题（默认设置新创建系统）
在苹果文档中，提及Xcode10中的关于旧项目New Build System更改适配中提及到以下两点
1、The new build system has stricter checks for cycles between elements in the build in order to prevent unnecessary rebuilds.
2、It is an error for any individual file in the build to be produced by more than one build command. For example, if two targets each declare the same output file from a shell script phase, factor out the declaration of the output file into a single target.
New Build System会对构建中的元素循环进行严格的检查，避免不必要的重建，这个也是错误出现的原因。
针对Xcode10（默认设置新创建系统）进行一下操作即可适应老项目不报错：
1、2、
老项目OK了
报错：
xxx has conflicting provisioning settings.xxx is automatically signed, but provisioning profile b9c32186-a5ad-43dd-a910-1c639b1ad5c3 has been manually specified. Set the provisioning profile value to “Automatic” in the build settings editor, or switch to manual signing in the project editor.
重复文件的报错，删除相应的文件即可：
用Xcode10跑之前的项目，也就报了一种类型的错误：Multiple commands produce。这个的原因是项目中使用第三方库，里面有README.md，README.txt，LICENSE，Info.plist之类的，而且是不止一个库中有，重复的这些文件，导致的报错。
解决方案（如图）：找到对应得第三方库的 target > Build phase > Copy Bundle Resource/Compile Sources，删掉第三方库中重复的上述文件即可。
或者另一种解决方法:打开项目的project.pbxproj文件，全局搜索b9c32186-a5ad-43dd-a910-1c639b1ad5c3，把指定行删除然后保存即可
文章参考链接：
https://blog.csdn.net/lining1041204250/article/details/82810417
https://www.jianshu.com/p/ebe95e2c4b05