--- a/libpam-sys/libpam-sys-helpers/build.rs	Sun Jul 06 19:23:02 2025 -0400
+++ b/libpam-sys/libpam-sys-helpers/build.rs	Mon Jul 07 12:11:43 2025 -0400
@@ -1,96 +1,6 @@
-#![allow(unexpected_cfgs)]
-
-use std::ffi::{c_void, CString};
-use std::ptr::NonNull;
-use std::{env, fs};
-
-include!("src/pam_impl.rs");
+use libpam_sys_consts::pam_impl;
 
 fn main() {
-    let pam_impl = match option_env!("LIBPAMSYS_IMPL") {
-        // The default option: Guess what PAM impl we're using based on OS.
-        None | Some("") => LibPam::detect(),
-        Some(other) => match PamImpl::try_from(other) {
-            Ok(i) => i,
-            Err(_) => {
-                panic!(
-                    "unknown PAM implementation {other:?}. valid LIBPAMSYS_IMPLs are {:?}, or unset to detect", PamImpl::items()
-                )
-            }
-        },
-    };
-    let impl_str = format!("{pam_impl:?}");
-    println!("{}", generate_cfg(&impl_str));
-    // We set this environment variable to substitute into docstrings.
-    println!("cargo:rustc-env=LIBPAMSYS_IMPL={impl_str}");
-    fs::write(
-        format!("{}/pam_impl_const.rs", env::var("OUT_DIR").unwrap()),
-        generate_consts(&impl_str),
-    )
-    .unwrap();
-}
-
-fn generate_consts(impl_str: &str) -> String {
-    format!(
-        "\
-impl PamImpl {{
-/// The implementation of libpam this was built for (`{impl_str}`).
-pub const CURRENT: Self = Self::{impl_str};
-}}
-
-/// String name of [`PamImpl::CURRENT`], for substituting into docs.
-#[macro_export]
-macro_rules! pam_impl_name {{ () => ({impl_str:?}) }}
-        "
-    )
+    println!("cargo:rustc-link-lib=pam");
+    pam_impl::enable_pam_impl_cfg();
 }
-
-struct LibPam(NonNull<c_void>);
-
-impl LibPam {
-    fn detect() -> PamImpl {
-        if let Some(lib) = Self::open() {
-            if lib.has("pam_syslog") {
-                return PamImpl::LinuxPam;
-            } else if lib.has("_openpam_log") {
-                return PamImpl::OpenPam;
-            } else if lib.has("__pam_get_authtok") {
-                return PamImpl::Sun;
-            }
-        }
-        if cfg!(target_os = "linux") {
-            PamImpl::LinuxPam
-        } else if cfg!(any(
-            target_os = "macos",
-            target_os = "freebsd",
-            target_os = "netbsd",
-            target_os = "dragonfly",
-            target_os = "openbsd",
-        )) {
-            PamImpl::OpenPam
-        } else if cfg!(any(target_os = "illumos", target_os = "solaris")) {
-            PamImpl::Sun
-        } else {
-            PamImpl::XSso
-        }
-    }
-
-    fn open() -> Option<Self> {
-        NonNull::new(unsafe { libc::dlopen(b"libpam.so\0".as_ptr().cast(), libc::RTLD_LAZY) })
-            .map(Self)
-    }
-
-    fn has(&self, name: &str) -> bool {
-        let name = CString::new(name).unwrap();
-        let symbol = unsafe { libc::dlsym(self.0.as_ptr(), name.as_ptr()) };
-        !symbol.is_null()
-    }
-}
-
-impl Drop for LibPam {
-    fn drop(&mut self) {
-        unsafe {
-            libc::dlclose(self.0.as_ptr());
-        }
-    }
-}