Wikipedia says "The UNIX Subsystem is built in to the Enterprise and Ultimate editions of Windows Vista". Does this mean I can compile POSIX programs in Visual Studio on Vista Ultimate? Well, I just tried that and Visual Studio can't find <unistd.h>

Code:
#include <unistd.h>

int main() {
    char mycwd[255];
    if (getcwd(mycwd, 255) == NULL) {
        perror ("Failed to get current working directory");
        return 1;
    }
    printf("Current working directory: %s\n", mycwd);
    return 0;
}