Turn assert functionality standard-conforming in jerry-libc

Introducing the `assert.h` public header with the `assert(x)` macro
and already making use of it in jerry-libc sources. These newly
introduced ISO C-conforming features replace the non-conforming
`LIBC_ASSERT` and `LIBC_NDEBUG` at no cost, and they also have the
benefit that we can expose `assert` in a public header and make it
useful to jerry-libc users.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

jerry-libc/jerry-libc-defs.h

@@ -1,4 +1,4 @@
-/* Copyright 2015 Samsung Electronics Co., Ltd.
+/* Copyright 2015-2016 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.
@@ -28,30 +28,4 @@
 #define __attr_noreturn___ __attribute__((noreturn))
 #define __attr_noinline___ __attribute__((noinline))
 
-/**
- * Assertions
- */
-extern void __attr_noreturn___
-libc_fatal (const char *msg,
-            const char *file_name,
-            const char *function_name,
-            const unsigned int line_number);
-
-#ifndef LIBC_NDEBUG
-# define LIBC_ASSERT(x) do { if (__builtin_expect (!(x), 0)) { \
-     libc_fatal (#x, __FILE__, __func__, __LINE__); } } while (0)
-# define LIBC_UNREACHABLE() \
-   do \
-   { \
-     libc_fatal ("Code is unreachable", __FILE__, __func__, __LINE__); \
-   } while (0)
-#else /* !LIBC_NDEBUG */
-# define LIBC_ASSERT(x) do { if (false) { (void) (x); } } while (0)
-# define LIBC_UNREACHABLE() \
-   do \
-   { \
-     libc_fatal (NULL, NULL, NULL, 0); \
-   } while (0)
-#endif /* !LIBC_NDEBUG */
-
 #endif /* !DEFS_H */