17         println!("cargo:rustc-check-cfg=cfg(fuzzing)");  in main()
18         println!("cargo:rustc-check-cfg=cfg(no_is_available)");  in main()
19         println!("cargo:rustc-check-cfg=cfg(no_literal_byte_character)");  in main()
20         println!("cargo:rustc-check-cfg=cfg(no_literal_c_string)");  in main()
21         println!("cargo:rustc-check-cfg=cfg(no_source_text)");  in main()
22         println!("cargo:rustc-check-cfg=cfg(proc_macro_span)");  in main()
23         println!("cargo:rustc-check-cfg=cfg(procmacro2_backtrace)");  in main()
24         println!("cargo:rustc-check-cfg=cfg(procmacro2_nightly_testing)");  in main()
25         println!("cargo:rustc-check-cfg=cfg(procmacro2_semver_exempt)");  in main()
26         println!("cargo:rustc-check-cfg=cfg(randomize_layout)");  in main()
27         println!("cargo:rustc-check-cfg=cfg(span_locations)");  in main()
28         println!("cargo:rustc-check-cfg=cfg(super_unstable)");  in main()
29         println!("cargo:rustc-check-cfg=cfg(wrap_proc_macro)");  in main()
35         // https://github.com/dtolnay/proc-macro2/issues/147  in main()
36         println!("cargo:rustc-cfg=procmacro2_semver_exempt");  in main()
39     if semver_exempt || cfg!(feature = "span-locations") {  in main()
43         println!("cargo:rustc-cfg=span_locations");  in main()
48         // macro API is available vs needs to be polyfilled. Instead, use the  in main()
49         // proc macro API unconditionally and catch the panic that occurs if it  in main()
51         println!("cargo:rustc-cfg=no_is_available");  in main()
56         println!("cargo:rustc-cfg=no_source_text");  in main()
62         println!("cargo:rustc-cfg=no_literal_byte_character");  in main()
63         println!("cargo:rustc-cfg=no_literal_c_string");  in main()
66     if !cfg!(feature = "proc-macro") {  in main()
67         println!("cargo:rerun-if-changed=build.rs");  in main()
71     println!("cargo:rerun-if-changed=build/probe.rs");  in main()
89             // This compiler does not support the proc macro Span API in the  in main()
90             // form that proc-macro2 expects. No need to pay attention to  in main()
102         // macro Span API in the form that proc-macro2 expects, but try again if  in main()
109         // Wrap types from libproc_macro rather than polyfilling the whole API.  in main()
111         // can't emulate the unstable API without emulating everything else.  in main()
114         // nightly-only proc_macro API.  in main()
115         println!("cargo:rustc-cfg=wrap_proc_macro");  in main()
119         // Enable non-dummy behavior of Span::start and Span::end methods which  in main()
121         // nightly, unless `-Z allow-feature` in RUSTFLAGS disallows unstable  in main()
123         println!("cargo:rustc-cfg=proc_macro_span");  in main()
127         // Implement the semver exempt API in terms of the nightly-only  in main()
128         // proc_macro API.  in main()
129         println!("cargo:rustc-cfg=super_unstable");  in main()
133         println!("cargo:rerun-if-env-changed=RUSTC_BOOTSTRAP");  in main()
137 fn compile_probe(rustc_bootstrap: bool) -> bool {  in compile_probe()
139         // We are running inside rustc bootstrap. This is a highly non-standard  in compile_probe()
142         //     https://github.com/rust-lang/cargo/issues/11138  in compile_probe()
143         //     https://github.com/rust-lang/rust/issues/114839  in compile_probe()
176         .arg("--edition=2021")  in compile_probe()
177         .arg("--crate-name=proc_macro2")  in compile_probe()
178         .arg("--crate-type=lib")  in compile_probe()
179         .arg("--cap-lints=allow")  in compile_probe()
180         .arg("--emit=dep-info,metadata")  in compile_probe()
181         .arg("--out-dir")  in compile_probe()
186         cmd.arg("--target").arg(target);  in compile_probe()
203     // Clean up to avoid leaving nondeterministic absolute paths in the dep-info  in compile_probe()
216 fn rustc_minor_version() -> Option<u32> {  in rustc_minor_version()
218     let output = Command::new(rustc).arg("--version").output().ok()?;  in rustc_minor_version()
219     let version = str::from_utf8(&output.stdout).ok()?;  in rustc_minor_version()  localVariable
220     let mut pieces = version.split('.');  in rustc_minor_version()
227 fn cargo_env_var(key: &str) -> OsString {  in cargo_env_var()