`./configure` doesn't support lists

[jyn514]

I tried this code:

../configure --set rust.codegen-backends=[rustc_codegen_cranelift]

I expected to see this happen: configure generates

[rust]
codegen-backends = ["rustc_codegen_cranelift"]

Instead, this happened: configure generates

[rust]
codegen-backends = '[rustc_codegen_cranelift]'

which fails to parse.

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HEAD is branched from 13afbda

[jyn514]

./configure --set rust.codegen-backends='["rustc_codegen_cranelift"]' also doesn't work, it just embeds the quotes.

codegen-backends = '["rustc_codegen_cranelift"]'