How to write my own version of `std::nearbyint`

I want to write my own version of std::nearbyint which takes a float & returns the nearest int. This is because, it doesn't build on android gcc with ndk 14b. Something like this suggested for std::round.

Is it feasible ? any suggestions ?

I am using qmake with android gcc & it seems ridiculously difficult to build this math function no matter whatever compiler flag I use. tried the suggestions here & here. But, the problem seems to be that some math functions are missing in android gcc as suggested in ndk issues