It is pretty pointless to go back to history to see who's land it was. Like they say, the victor write history.
So what matters is who is in majority and who controls the military and the economy. In Singapore, Chinese control all. In Malaysia, the Malays are the majority, they control military but the Chinese control the economy.
If you take a look at the map of Middle East, you will notice that the borders have straight lines. Some British Governor during the colonial days (they held the military power) maybe even during afternoon tea, took out ruler and divided the whole Middle East and much of Africa too.
In the USA, land of democracy, the Red Indians where there first but now are segregated into reservations. Why, because the new immigrants controlled the economy, the military power and are the majority. So if you are native American just adapt with reality no point harping about ancestral lands.
So this is the fact of life and the best way is to learn to live with each other; something we have done for many years and is the unique flavor of Singapore. Another way is to immigrate. Does Malaysia easily give out citizenship to Singaporean Malays (do they see ethnicity or citizenship? I know that there are many Eurasians that have immigrated to Perth.
In short all this talk about ancestral land etc etc is pointless. If you want land, study hard, get a good job, work hard and go buy yourself a nice piece of land in Singapore. Ng teng fong worked hard, and worked smart and today his family owns large pieces of choice property over singapore