Merge branch 'dashu' of https://github.com/coasys/scryer-prolog into coasys-dashu

Cargo.toml

@@ -13,7 +13,6 @@ build = "build/main.rs"
 rust-version = "1.63"
 
 [features]
-default = ["rug"]
 
 [build-dependencies]
 indexmap = "1.0.2"
@@ -45,7 +44,6 @@ ctrlc = "3.2.2"
 ordered-float = "2.6.0"
 phf = { version = "0.9", features = ["macros"] }
 ref_thread_local = "0.0.0"
-rug = { version = "1.15.0", optional = true }
 rustyline = "12.0.0"
 ring = "0.16.13"
 ripemd160 = "0.8.0"
@@ -64,12 +62,14 @@ ryu = "1.0.9"
 hyper = { version = "1.0.0-rc.3", features = ["full"] }
 tokio = { version = "1.28.2", features = ["full"] }
 futures = "0.3"
-libffi = "3.1.0"
 libloading = "0.7"
 derive_deref = "1.1.1"
 http-body-util = "0.1.0-rc.2"
 bytes = "1"
 reqwest = { version = "0.11.18", features = ["blocking"] }
+dashu = { git = "https://github.com/coasys/dashu.git"  }
+libffi = { git = "https://github.com/coasys/libffi-rs.git", branch = "windows-space" }
+rand = "0.8.5"
 
 [dev-dependencies]
 assert_cmd = "1.0.3"