升级到Xcode12后报的错误如下：
- 如果是三方库比如友盟推送出现了以前的SDK1.3.0版本，而现在是2.5.2版本，则在Build Setting中Library Search Paths中删除1.3.0版本
-
重新选择New Build System，另一个弃用了
-
模拟器报错，报错代码如下
ld: in /Users/mac126/Desktop/项目名/Pods/BaiduMapKit/BaiduMapKit/BaiduMapAPI_Base.framework/BaiduMapAPI_Base(BMSDKKeychainItemWrapper.o), building for iOS Simulator, but linking in object file built for iOS, file '/Users/mac126/Desktop/项目名/Pods/BaiduMapKit/BaiduMapKit/BaiduMapAPI_Base.framework/BaiduMapAPI_Base' for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Xcode12 没有VALID_ARCHS，手动添加VALID_ARCHS，加一个x86_64
-
真机运行报以下错
新加一个arm64 即可真机运行
但是加上x86_64后模拟器能运行，真机报错，加上x86_64和arm64后，真机能运行，模拟器报错。
所以不支持模拟器arm64架构，要排除arm64架构，解决如下：
Build Settings -> Excluded Architectures
以上配置完，真机和模拟器都能运行
- ld: library not found for -lstdc++.6.0.9
手动加入
将文件夹的内容拷贝到对应路径下即可
平台 文件夹 文件 大小 路径
模拟器运行 CoreSimulator libstdc++.6.0.9.dylib 766,624B /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib/
模拟器编译 iPhoneSimulator libstdc++.6.0.9.tbd 206,800B /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/usr/lib/
iOS真机 iPhoneOS libstdc++.6.0.9.tbd 209,673B /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/lib/
macAPP MacOSX libstdc++.6.0.9.tbd 206,751B /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/
模拟器运行和编译我把三个文件（libstdc++.6，libstdc++.6.0.9，libstdc++）全部加入，真机只加入6.0.9
6.0.9文件下载地址
链接: https://pan.baidu.com/s/1oDTkWi7htRgLY84mDis73Q
密码: 0d5g
