There is an official RPi distro that has most of the standard GNU & other open source software built for the RPi. The distro can be copied to an SD flash, from which the RPi will boot. There is a working cross toolchain to build most other things using a conventional x86 Linux host. I have used it, and it works fine. I think there is a native toolchain in the distro, but doing software development on such a resource constrained system would be very slow.
Do not expect x86 binaries to work at all on any non-x86 platform (or vice-versa).
Since the Pi has little or no storage capability, using it as a NAS server seems like a curious application.