Let aliases in `.cargo/config.toml` specify environment variables

[not-my-profile]

Problem

The [alias] table in .cargo/config.toml lets you define command aliases but it doesn't let you specify environment variables for these commands.

Proposed Solution

Support environment variables to be specified as follows:

[alias]
docsrs = {command="doc", env={RUSTDOCFLAGS="--cfg docsrs"}}

Notes

No response

[epage]

While this solution is much lighter weight, if we went the deno route of a cross-platform shell-like language, like duckscript, this could be specified in the command itself.

[weihanglo]

The proposed solution might not be easy to set via CARGO_ALIAS_* environment variable, though with -Zadvanced-env (#7406) it should become trivial.