Building for older os

[mercurial-moon]

Hi,

I try to build railroad_dsl with an older toolchain (1.77) for making it work Windows 7. My build system has a newer OS however I want to run the built exe on older os like Windows 7.

While building I get error like

error[E0658]: use of unstable library feature 'lazy_cell' on render.rs line 67 67 | static USVG_OPTS: std::sync::LazyLockresvg::usvg::Options = std::sync::LazyLock::new(|| {