linkat
# define linkat(toFD, toPath, pathFD, path, flag) \
linkat(int oldFD, const char *oldPath, int newFD, const char *newPath,
linkat(int toFD, const char* toPath, int pathFD, const char* path, int flag)
linkat(int toFD, const char *toPath, int linkFD, const char *linkPath, int flag)
void linkat() {}
void linkat() {}