1 files changed, 73 insertions, 0 deletions
diff --git a/vendor/semver/build.rs b/vendor/semver/build.rs
new file mode 100644
index 000000000..b45af7e23
--- /dev/null
+++ b/vendor/semver/build.rs
@@ -0,0 +1,73 @@
+use std::env;
+use std::process::Command;
+use std::str;
+
+fn main() {
+    let compiler = match rustc_minor_version() {
+        Some(compiler) => compiler,
+        None => return,
+    };
+
+    if compiler < 33 {
+        // Exhaustive integer patterns. On older compilers, a final `_` arm is
+        // required even if every possible integer value is otherwise covered.
+        // https://github.com/rust-lang/rust/issues/50907
+        println!("cargo:rustc-cfg=no_exhaustive_int_match");
+    }
+
+    if compiler < 36 {
+        // extern crate alloc.
+        // https://blog.rust-lang.org/2019/07/04/Rust-1.36.0.html#the-alloc-crate-is-stable
+        println!("cargo:rustc-cfg=no_alloc_crate");
+    }
+
+    if compiler < 39 {
+        // const Vec::new.
+        // https://doc.rust-lang.org/std/vec/struct.Vec.html#method.new
+        println!("cargo:rustc-cfg=no_const_vec_new");
+    }
+
+    if compiler < 40 {
+        // #[non_exhaustive].
+        // https://blog.rust-lang.org/2019/12/19/Rust-1.40.0.html#non_exhaustive-structs-enums-and-variants
+        println!("cargo:rustc-cfg=no_non_exhaustive");
+    }
+
+    if compiler < 45 {
+        // String::strip_prefix.
+        // https://doc.rust-lang.org/std/primitive.str.html#method.repeat
+        println!("cargo:rustc-cfg=no_str_strip_prefix");
+    }
+
+    if compiler < 46 {
+        // #[track_caller].
+        // https://blog.rust-lang.org/2020/08/27/Rust-1.46.0.html#track_caller
+        println!("cargo:rustc-cfg=no_track_caller");
+    }
+
+    if compiler < 52 {
+        // #![deny(unsafe_op_in_unsafe_fn)].
+        // https://github.com/rust-lang/rust/issues/71668
+        println!("cargo:rustc-cfg=no_unsafe_op_in_unsafe_fn_lint");
+    }
+
+    if compiler < 53 {
+        // Efficient intrinsics for count-leading-zeros and count-trailing-zeros
+        // on NonZero integers stabilized in 1.53.0. On many architectures these
+        // are more efficient than counting zeros on ordinary zeroable integers.
+        // https://doc.rust-lang.org/std/num/struct.NonZeroU64.html#method.leading_zeros
+        // https://doc.rust-lang.org/std/num/struct.NonZeroU64.html#method.trailing_zeros
+        println!("cargo:rustc-cfg=no_nonzero_bitscan");
+    }
+}
+
+fn rustc_minor_version() -> Option<u32> {
+    let rustc = env::var_os("RUSTC")?;
+    let output = Command::new(rustc).arg("--version").output().ok()?;
+    let version = str::from_utf8(&output.stdout).ok()?;
+    let mut pieces = version.split('.');
+    if pieces.next() != Some("rustc 1") {
+        return None;
+    }
+    pieces.next()?.parse().ok()
+}