Publically declare GlobalValue.

It's used in the publically declared FuncEnvironment trait, so library
users should be able to name it.

lib/wasm/src/lib.rs

@@ -24,6 +24,6 @@ mod state;
 mod translation_utils;
 
 pub use module_translator::{translate_module, TranslationResult};
-pub use runtime::{FuncEnvironment, WasmRuntime, DummyRuntime};
+pub use runtime::{FuncEnvironment, WasmRuntime, DummyRuntime, GlobalValue};
 pub use translation_utils::{FunctionIndex, GlobalIndex, TableIndex, MemoryIndex, SignatureIndex,
                             Global, GlobalInit, Table, Memory};