Add build configuration for Mac (#110)

* Add build configuration for Mac

This patch implements Mac build basically based on Linux platform
implementations and configurations.

The document to build it on Mac has been updated as well.

* Update wasm_application.h

* Update lib_export.h

Add comments for the functions.

core/iwasm/runtime/include/lib_export.h

@@ -40,7 +40,13 @@ int
 get_base_lib_export_apis(NativeSymbol **p_base_lib_apis);
 
 /**
- * Get the exported APIs of extend lib
+ * Get the exported APIs of extended lib, this API isn't provided by WASM VM,
+ * it must be provided by developer to register the extended native APIs,
+ * for example, developer can register his native APIs to extended_native_symbol_defs,
+ * array, and include file ext_lib_export.h which implements this API.
+ * And if developer hasn't any native API to register, he can define an empty
+ * extended_native_symbol_defs array, and then include file ext_lib_export.h to
+ * implements this API.
  *
  * @param p_base_lib_apis return the exported API array of extend lib
  *

core/iwasm/runtime/include/wasm_application.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2019 Taobao (China) Inc.  All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _WASM_APPLICATION_H
+#define _WASM_APPLICATION_H
+
+//#include "wasm_runtime.h"
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct WASMModuleInstance;
+
+/**
+ * Find the unique main function from a WASM module instance
+ * and execute that function.
+ *
+ * @param module_inst the WASM module instance
+ * @param argc the number of arguments
+ * @param argv the arguments array
+ *
+ * @return true if the main function is called, false otherwise and exception will be thrown,
+ *   the caller can call wasm_runtime_get_exception to get exception info.
+ */
+bool
+wasm_application_execute_main(struct WASMModuleInstance *module_inst,
+                              int argc, char *argv[]);
+
+/**
+ * Find the specified function in argv[0] from a WASM module instance
+ * and execute that function.
+ *
+ * @param module_inst the WASM module instance
+ * @param name the name of the function to execute
+ * @param argc the number of arguments
+ * @param argv the arguments array
+ *
+ * @return true if the specified function is called, false otherwise and exception will be thrown,
+ *   the caller can call wasm_runtime_get_exception to get exception info.
+ */
+bool
+wasm_application_execute_func(struct WASMModuleInstance *module_inst,
+                              char *name, int argc, char *argv[]);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* end of _WASM_APPLICATION_H */
+