fix(lib): enable building for windows targets

- conditionally build diag_device.rs only for unix
- use build time target for runtime metadata on unix

lib/src/lib.rs

@@ -1,6 +1,5 @@
 pub mod hdlc;
 pub mod diag;
-pub mod diag_device;
 pub mod qmdl;
 pub mod log_codes;
 pub mod gsmtap;
@@ -9,5 +8,9 @@ pub mod pcap;
 pub mod analysis;
 pub mod util;
 
+// bin/check.rs may target windows and does not use this mod
+#[cfg(target_family = "unix")]
+pub mod diag_device;
+
 // re-export telcom_parser, since we use its types in our API
 pub use telcom_parser;