Move the wasmtime crate directories form lib/* to wasmtime-*.

This follows a similar change to Cranelift made here:

https://github.com/CraneStation/cranelift/pull/660

wasmtime-obj/src/data_segment.rs

@@ -0,0 +1,32 @@
+use faerie::{Artifact, Decl};
+use wasmtime_environ::DataInitializer;
+
+/// Declares data segment symbol
+pub fn declare_data_segment(
+    obj: &mut Artifact,
+    _data_initaliazer: &DataInitializer,
+    index: usize,
+) -> Result<(), String> {
+    let name = format!("_memory_{}", index);
+    obj.declare(
+        name,
+        Decl::Data {
+            writable: false,
+            global: false,
+        },
+    )
+    .map_err(|err| format!("{}", err))?;
+    Ok(())
+}
+
+/// Emit segment data and initialization location
+pub fn emit_data_segment(
+    obj: &mut Artifact,
+    data_initaliazer: &DataInitializer,
+    index: usize,
+) -> Result<(), String> {
+    let name = format!("_memory_{}", index);
+    obj.define(name, Vec::from(data_initaliazer.data))
+        .map_err(|err| format!("{}", err))?;
+    Ok(())
+}