To build OOo under ARM, (an apparently massively popular hobby in China at the moment for some reason other), try downloading the normal source from www.openoffice.org and…
that should go a long way. Though for < 3.2 you may need (ooo#100469) applied.
Of course, given that ARM isn’t generally fast, then there are likely cross-compilers, qemu-user hackery, or other stuff involved, but nothing specific to OOo, so if you can, say, build gedit with your environment, then OOo should generally build fine too. Try the same hackery you’d try with a simpler project with OOo.
And it is not porting something to simply build it. You actively have to change something before bandying around the term porting