extern crate autocfg; use std::env; fn main() { let ac = autocfg::new(); // If the "i128" feature is explicity requested, don't bother probing for it. // It will still cause a build error if that was set improperly. if env::var_os("CARGO_FEATURE_I128").is_some() || ac.probe_type("i128") { autocfg::emit("has_i128"); } ac.emit_expression_cfg( "unsafe { 1f64.to_int_unchecked::() }", "has_to_int_unchecked", ); ac.emit_expression_cfg("1u32.reverse_bits()", "has_reverse_bits"); ac.emit_expression_cfg("1u32.trailing_ones()", "has_leading_trailing_ones"); ac.emit_expression_cfg("{ let mut x = 1; x += &2; }", "has_int_assignop_ref"); ac.emit_expression_cfg("1u32.div_euclid(1u32)", "has_div_euclid"); if env::var_os("CARGO_FEATURE_STD").is_some() { ac.emit_expression_cfg("1f64.copysign(-1f64)", "has_copysign"); } autocfg::rerun_path("build.rs"); }