No longer building for toltec

[0x00002a]

Building with normal cargo build works, however make toltec exits with:

   Compiling proc-macro2 v1.0.46
error[E0635]: unknown feature `proc_macro_span_shrink`
  --> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.46/src/lib.rs:92:30
   |
92 |     feature(proc_macro_span, proc_macro_span_shrink)
   |                              ^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0635`.
error: could not compile `proc-macro2`

I found a github issue on another package saying they fixed it by pinning proc-macro2 to 1.0.43, but I don't know enough about how this project builds to fix it