* gnu/packages/crates-io.scm (rust-pyo3-macros-0.19): New variable. (rust-pyo3-macros-0.16): Inherit from rust-pyo3-macros-0.19.
* gnu/packages/crates-io.scm (rust-pyo3-macros-0.19): New variable. (rust-pyo3-macros-0.16): Inherit from rust-pyo3-macros-0.19.