Project ERROR: Cannot run target compiler '/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++'. Output:

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Maybe you forgot to setup the environment?

解决
找到这个文件，并打开
Qt5.15/5.15.1/ios/mkspecs/features/toolchain.prf

第202行

!equals(ec, 0): qtCompilerError($$QMAKE_CXX, $$output)

修改为

!uikit:!equals(ec, 0): qtCompilerError($$QMAKE_CXX, $$output)