1 files changed, 1 insertions, 38 deletions
diff --git a/build.rs b/build.rs
index 0e12602..dd09e62 100644
--- a/build.rs
+++ b/build.rs
@@ -1,6 +1,4 @@
 use std::env;
-use std::process::Command;
-use std::str::{self, FromStr};
 
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
@@ -9,46 +7,11 @@ fn main() {
     // src/lexical/math.rs for where this has an effect.
     let target_arch = env::var("CARGO_CFG_TARGET_ARCH").unwrap();
     match target_arch.as_str() {
-        "aarch64" | "mips64" | "powerpc64" | "x86_64" => {
+        "aarch64" | "mips64" | "powerpc64" | "x86_64" | "loongarch64" => {
             println!("cargo:rustc-cfg=limb_width_64");
         }
         _ => {
             println!("cargo:rustc-cfg=limb_width_32");
         }
     }
-
-    let minor = match rustc_minor_version() {
-        Some(minor) => minor,
-        None => return,
-    };
-
-    // BTreeMap::get_key_value
-    // https://blog.rust-lang.org/2019/12/19/Rust-1.40.0.html#additions-to-the-standard-library
-    if minor < 40 {
-        println!("cargo:rustc-cfg=no_btreemap_get_key_value");
-    }
-
-    // BTreeMap::remove_entry
-    // https://blog.rust-lang.org/2020/07/16/Rust-1.45.0.html#library-changes
-    if minor < 45 {
-        println!("cargo:rustc-cfg=no_btreemap_remove_entry");
-    }
-
-    // BTreeMap::retain
-    // https://blog.rust-lang.org/2021/06/17/Rust-1.53.0.html#stabilized-apis
-    if minor < 53 {
-        println!("cargo:rustc-cfg=no_btreemap_retain");
-    }
-}
-
-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;
-    }
-    let next = pieces.next()?;
-    u32::from_str(next).ok()
 }