sgx target_env

How the `#[cfg(target_env = "sgx")]` in libstd, libc etc. affects this SDK?
is this the dream of SGX being integrated into the SDK?

will this SDK someday leverage that to natively compile rust code into sgx?

i.e. https://github.com/rust-lang/rust/blob/f843ad60ef5a78d8b4da85c5007d3ecac229f1a8/src/libstd/sys/mod.rs#L44

Start with the linked Rust libstd sys/mod.rs entry point and inspect how the SDK handles `#[cfg(target_env = "sgx")]` in libstd and libc. Document whether this configuration is integrated into the SDK and whether Rust code can be natively compiled for SGX; the issue is done when these questions are answered clearly.

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