Logging, macros, and building: - Changes logging API to accept the `Location` of the log statement. Fixes OpenPAM implementation. - Stops publicly exporting doc macros. - Uses dlopen to detect the PAM library rather than header jankery.

--- a/src/lib.rs	Sun Jun 29 03:35:59 2025 -0400
+++ b/src/lib.rs	Sun Jun 29 18:27:51 2025 -0400
@@ -32,6 +32,7 @@
 pub mod handle;
 
 mod _doc;
+pub(crate) use _doc::*;
 mod environ;
 #[cfg(feature = "link")]
 mod libpam;