NDEBUG defined in btree.h

[GoogleCodeExporter]

What steps will reproduce the problem?

1. Compile and run a program like:

#undef NDEBUG

#include "btree_set.h"
#include <cassert>

int main (void) {
    assert(false);
}

What is the expected output? What do you see instead?

The assertion should fail. Instead the assertion is skipped since btree.h has 
defined NDEBUG to 1. Reversing the order of includes would paper over the issue.

Original issue reported on code.google.com by jsn...@gmail.com on 3 May 2013 at 10:36