Xcode project file generation does not work in macOS 11 Big Sur

[olzhas]

Hello,

it seems that installation instructions should be updated.

Since, the following line does not create an Xcode project file.

dartsim.github.io/pages/install_dart_on_mac.md

Line 101 in e15a145

$ cmake .. -G Xcode

I propose a temporary solution where we just force cmake to create legacy xcode project file. In this case we just need to change the line to

cmake .. -G Xcode -T buildsystem=1

Please find the link to the source of the temporary solution:
https://stackoverflow.com/questions/65473503/when-trying-to-generate-an-xcode-project-from-a-cmake-folder-i-get-an-error-rel

[olzhas]

I can create a pull request to fix this, however I am not sure what will be the best thing to do.