Attempt to placate the OSX buildslaves, which do not appreciate multiple

definitions of `assert'

toku_include/toku_assert.h

@@ -140,6 +140,9 @@ extern void (*do_assert_hook)(void); // Set this to a function you want called a
 #define assert_zero(expr) toku_do_assert((expr) == 0, #expr, __FUNCTION__, __FILE__, __LINE__, get_maybe_error_errno())
 #define assert_equals(expr, expected) toku_do_assert((expr) == (expected), (expected), #expr, __FUNCTION__, __FILE__, __LINE__, get_maybe_error_errno())
 #else
+#ifdef assert
+#  undef assert // some compilers do not like multiple definitions of a single macro - so undef the existing assert def here
+#endif
 #define assert(expr)      ((expr)      ? (void)0 : toku_do_assert_fail(#expr, __FUNCTION__, __FILE__, __LINE__, get_maybe_error_errno()))
 #define assert_zero(expr) ((expr) == 0 ? (void)0 : toku_do_assert_zero_fail((uintptr_t)(expr), #expr, __FUNCTION__, __FILE__, __LINE__, get_maybe_error_errno()))
 #define assert_equals(expr, expected) ((expr) == (expected) ? (void)0 : toku_do_assert_expected_fail((uintptr_t)(expr), (uintptr_t)(expected), #expr, __FUNCTION__, __FILE__, __LINE__, get_maybe_error_errno()))