Introducing jerry-libc's interface include directory.

jerry-libc/include/stdlib.h

@@ -0,0 +1,27 @@
+/* Copyright 2015 Samsung Electronics Co., Ltd.
+ *
+ * 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 JERRY_LIBC_STDLIB_H
+#define JERRY_LIBC_STDLIB_H
+
+#ifdef __cplusplus
+# define EXTERN_C "C"
+#else /* !__cplusplus */
+# define EXTERN_C
+#endif /* !__cplusplus */
+
+extern EXTERN_C void __attribute__ ((noreturn)) exit (int);
+
+#endif /* !JERRY_LIBC_STDLIB_H */