const SP_INCLUDE: &str = "DEP_SERVICEPOINT_INCLUDE"; fn main() { println!("cargo::rerun-if-changed=src/main.c"); println!("cargo::rerun-if-changed=build.rs"); println!("cargo::rerun-if-env-changed={SP_INCLUDE}"); let sp_include = std::env::var_os(SP_INCLUDE).unwrap().into_string().unwrap(); // this builds a lib, this is only to check that the example compiles let mut cc = cc::Build::new(); cc.file("src/main.c"); cc.include(&sp_include); cc.opt_level(2); cc.compile("lang_c"); }