Move library crates under 'lib/'.

Give these crates each a more standard directory layout with sources in
a 'src' sub-sirectory and Cargo.toml in the top lib/foo directory.

Add license and description fields to each.

The build script for the cretonne crate now lives in
'lib/cretonne/build.rs' separating it from the normal library sources
under 'lib/cretonne/src'.

lib/cretonne/src/isa/riscv/settings.rs

@@ -0,0 +1,49 @@
+//! RISC-V Settings.
+
+use settings::{self, detail, Builder};
+use std::fmt;
+
+// Include code generated by `meta/gen_settings.py`. This file contains a public `Flags` struct
+// with an impl for all of the settings defined in `meta/cretonne/settings.py`.
+include!(concat!(env!("OUT_DIR"), "/settings-riscv.rs"));
+
+#[cfg(test)]
+mod tests {
+    use super::{builder, Flags};
+    use settings::{self, Configurable};
+
+    #[test]
+    fn display_default() {
+        let shared = settings::Flags::new(&settings::builder());
+        let b = builder();
+        let f = Flags::new(&shared, &b);
+        assert_eq!(f.to_string(),
+                   "[riscv]\n\
+                    supports_m = false\n\
+                    supports_a = false\n\
+                    supports_f = false\n\
+                    supports_d = false\n\
+                    enable_m = true\n");
+        // Predicates are not part of the Display output.
+        assert_eq!(f.full_float(), false);
+    }
+
+    #[test]
+    fn predicates() {
+        let shared = settings::Flags::new(&settings::builder());
+        let mut b = builder();
+        b.set_bool("supports_f", true).unwrap();
+        b.set_bool("supports_d", true).unwrap();
+        let f = Flags::new(&shared, &b);
+        assert_eq!(f.full_float(), true);
+
+        let mut sb = settings::builder();
+        sb.set_bool("enable_simd", false).unwrap();
+        let shared = settings::Flags::new(&sb);
+        let mut b = builder();
+        b.set_bool("supports_f", true).unwrap();
+        b.set_bool("supports_d", true).unwrap();
+        let f = Flags::new(&shared, &b);
+        assert_eq!(f.full_float(), false);
+    }
+}