Support is_library_threadsafe() for older HDF5

Author: aldanor

src/lib.rs

@@ -125,10 +125,17 @@ pub fn library_version() -> (u8, u8, u8) {
 
 /// Returns true if the HDF5 library is threadsafe.
 pub fn is_library_threadsafe() -> bool {
-    use self::internal_prelude::hbool_t;
-    use hdf5_sys::h5::H5is_library_threadsafe;
-    let mut ts: hbool_t = 0;
-    h5call!(H5is_library_threadsafe(&mut ts)).map(|_| ts > 0).unwrap_or(false)
+    #[cfg(hdf5_1_8_16)]
+    {
+        use self::internal_prelude::hbool_t;
+        use hdf5_sys::h5::H5is_library_threadsafe;
+        let mut ts: hbool_t = 0;
+        h5call!(H5is_library_threadsafe(&mut ts)).map(|_| ts > 0).unwrap_or(false)
+    }
+    #[cfg(not(hdf5_1_8_16))]
+    {
+        cfg!(h5_have_threadsafe)
+    }
 }
 
 #[cfg(test)]