Have the same problem with C::B 8.02 at Ubuntu (binary package from repos).
I was unable to find declaration of 'sleep' function explicitly declared in 'unistd.h' (always obtaining 'Not found:' message) in this simple piece of code:
#include <iostream>
#include <unistd.h>
using namespace std;
int main()
{
sleep(1);
cout << "Hello world!" << endl;
return 0;
}
though I added '/usr/include' and '/usr/include/c++/4.3.3' in global list of search directories, as wel as in the project options too. Maybe there are some external dependencies (ctags ?) need to be installed, or patches need to be applied on C::B source code, or anything else?