Function erg_common::spawn::exec_new_thread

pub fn exec_new_thread<F, T>(run: F) -> Twhere
    F: FnOnce() -> T + Send + 'static,
    T: Send + 'static,

Execute a function in a new thread on Windows, otherwise just run it.

Windows has a smaller default stack size than other OSs, which may cause a stack overflow, especially in the parsing process.