I don't know for crystalmake but you check all the prt* variable to write things in different format like xml, posca or cif.
Vesta will read for sure the cif and poscar file.
You can also generate a density file or potential file with prtden and use the cut3d tool included in abinit to produce a file that can be read by xcrysden.
An other option is to use Vsim with the abinit plugin to visualize the abinit input file.
Yet another tool is (still under heavy development but working) abiout which is available and ready to use on
linux mac and
windows. You can just drop an abinit input file or _OUT.nc file ou _HIST file in the main windows