Merge branch 'master' of https://github.com/mthom/scryer-prolog

src/prolog/machine/system_calls.rs

@@ -1302,11 +1302,7 @@ impl MachineState {
                 let result = {
                     let mut rand = RANDOM_STATE.borrow_mut();
 
-                    if rand.bits(1) == 0 {
-                        true
-                    } else {
-                        false
-                    }
+                    rand.bits(1) == 0
                 };
 
                 self.fail = result;

src/prolog/mod.rs

@@ -1,8 +1,11 @@
 extern crate dirs;
 extern crate ordered_float;
 extern crate prolog_parser;
+#[cfg(feature = "rug")]
 extern crate rug;
-extern crate rustyline;   
+#[cfg(feature = "num-rug-adapter")]
+extern crate num_rug_adapter as rug;
+extern crate rustyline;
 
 #[macro_use]
 mod macros;