mangle does mangle quite aggressively.

No unsafe code. The rest looks benign: the crate emits little bits of code
and runs them through the compiler to detect features. The test suite is
minimal but looks complete.

No unsafe code. The rest looks benign: the crate emits little bits of code
and runs them through the compiler to detect features. The test suite is
minimal but looks complete.

autocfg is a small and simple crate to be used in build scripts.

Code snippets are passed to rustc to detect if the available version supports
the desired features and can compile them. For completeness, it should be
mentioned that it would be a bad idea to use this with user inputs at
runtime. It is hard to do so accidantely.

LGTM, starts using RUSTFLAGS

Reads env vars and executes the program in them, or whatever program happens to be called rustc... but given that this thing's purpose is to probe rustc versions, that's kinda inevitable. Abuseable but certainly not malicious; it's made for build scripts and it's fine for this purpose.

0.1.6: LGTM
0.1.5: No unsafe code, minor safe-looking file I/O

No unsafe code, minor safe-looking file I/O