LibC: Hint the compiler that assertions rarely fail

Also, rewrite the macro to expand to an if statement instead of
a weird ternary operator with a (void)0 banch.

Libraries/LibC/assert.h

@@ -34,7 +34,11 @@ __BEGIN_DECLS
 __attribute__((noreturn)) void __assertion_failed(const char* msg);
 # define __stringify_helper(x) # x
 # define __stringify(x) __stringify_helper(x)
-# define assert(expr) ((expr) ? (void)0 : __assertion_failed(# expr "\n" __FILE__ ":" __stringify(__LINE__)));
+# define assert(expr) \
+ do { \
+ if (__builtin_expect(!(expr), 0)) \
+ __assertion_failed(#expr "\n" __FILE__ ":" __stringify(__LINE__)); \
+ } while (0)
 # define ASSERT_NOT_REACHED() assert(false)
 #else
 # define assert(expr)