The nixpkgs have a rather elegant way to deal with that. Let's presume you need a libpng for an armv7 platform, such as an old RaspberryPi. Then Nix allows you to

- get a suitable cross compiler toolchain

- pick whether you want dynamic or static linking (most likely static when the target system does not come with /nix/store)

- compile all prerequisites for the library such as transitive dependencies

- compile the library with the cross compiler for the selected target arch

All in one command line call, that does not require you to 'apt-get install' any of the tools manually:

  nix-build '<nixpkgs>' -A pkgsStatic.libpng --arg crossSystem '{ config = "armv7a-unknown-linux-gnueabihf"; }'