Library restructure (#104)

* Move wasmer-runtime to wasmer-runtime-core

* Add the runtime library

* Fix issue with macros using wasmer_runtime, fmt

* Make default compiler dependency optional

* Add instantiate and validate functions

lib/runtime-core/src/macros.rs

@@ -0,0 +1,89 @@
+macro_rules! debug {
+    ($fmt:expr) => (if cfg!(any(debug_assertions, feature="debug")) { println!(concat!("wasmer-runtime(:{})::", $fmt), line!()) });
+    ($fmt:expr, $($arg:tt)*) => (if cfg!(any(debug_assertions, feature="debug")) { println!(concat!("wasmer-runtime(:{})::", $fmt, "\n"), line!(), $($arg)*) });
+}
+
+#[macro_export]
+macro_rules! export_func {
+    ($func:ident, [ $( $params:ident ),* ] -> [ $( $returns:ident ),* ]) => {{
+        use $crate::{
+            export::{Context, Export, FuncPointer},
+            types::{FuncSig, Type},
+            vm,
+        };
+
+        let func: extern fn( $( $params, )* &mut vm::Ctx) -> ($( $returns )*) = $func;
+
+        Export::Function {
+            func: unsafe { FuncPointer::new(func as _) },
+            ctx: Context::Internal,
+            signature: FuncSig {
+                params: vec![$($crate::__export_func_convert_type!($params),)*],
+                returns: vec![$($crate::__export_func_convert_type!($returns),)*],
+            },
+        }
+    }};
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! __export_func_convert_type {
+    (i32) => {
+        Type::I32
+    };
+    (u32) => {
+        Type::I32
+    };
+    (i64) => {
+        Type::I64
+    };
+    (u64) => {
+        Type::I32
+    };
+    (f32) => {
+        Type::F32
+    };
+    (f64) => {
+        Type::F64
+    };
+    ($x:ty) => {
+        compile_error!("Only `i32`, `u32`, `i64`, `u64`, `f32`, and `f64` are supported for argument and return types")
+    };
+}
+
+#[macro_export]
+macro_rules! imports {
+    ( $( $ns_name:expr => $ns:tt, )* ) => {{
+        use $crate::{
+            import::{ImportObject, Namespace},
+        };
+
+        let mut import_object = ImportObject::new();
+
+        $({
+            let ns = $crate::__imports_internal!($ns);
+
+            import_object.register($ns_name, ns);
+        })*
+
+        import_object
+    }};
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! __imports_internal {
+    ( { $( $imp_name:expr => $func:ident < [ $( $params:ident ),* ] -> [ $( $returns:ident ),* ] >, )* } ) => {{
+        let mut ns = Namespace::new();
+        $(
+            ns.insert($imp_name, $crate::export_func!(
+                $func,
+                [ $( $params ),* ] -> [ $( $returns )* ]
+            ));
+        )*
+        ns
+    }};
+    ($ns:ident) => {
+        $ns
+    };
+}