Failed to compile

Hey guys I am new to ruby motion and wanna build my first app OSX and got type of errors
could you help how can I fix this
`
Build ./build/MacOSX-10.15-Development

Compile ./app/app_delegate.rb

Compile ./app/menu.rb

objc[63743]: +[NSPlaceholderMutableString initialize] may have been in progress in another thread when fork() was called.

objc[63743]: +[NSPlaceholderMutableString initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.

objc[63744]: +[NSPlaceholderMutableString initialize] may have been in progress in another thread when fork() was called.

objc[63744]: +[NSPlaceholderMutableString initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.

ERROR! File ‘./app/menu.rb’ failed to compile`

during this errors it suggested and I set the env RM_BYPASS_DOCTOR=1

could you help me?

Catalina gets a bit picky - have you also added

export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES

to your shell?