crosscompile to windows will fail with lld version < 14

[djytw]

e.g. w/ lld-link-12:

  = note: lld-link-12: error: undefined symbol: __guard_eh_cont_table
          >>> referenced by msvcrt.lib(loadcfg.obj):(_load_config_used)

          lld-link-12: error: undefined symbol: __guard_eh_cont_count
          >>> referenced by msvcrt.lib(loadcfg.obj):(_load_config_used)


The following warnings were emitted during compilation:

warning: GNU compiler is not supported for this target

error: could not compile `app` (bin "app") due to previous error
       Error failed to build app: failed to build app

followed https://askubuntu.com/a/1466862 to install lld-14 on ubuntu 1804 and it worked. Just make sure .cargo/config.toml use the correct version of lld