Fix potential arg processing error
Fix potential arg processing error

When no additional arguments were given on the left side of '-P build.cmake'

ishtoo/Reaping2,MrPepperoni/Reaping2-1,Reaping2/Reaping2,MrPepperoni/Reaping2-1,abannerth/Reaping2,Reaping2/Reaping2,HalalUr/Reaping2,ishtoo/Reaping2,HalalUr/Reaping2,weanti/Reaping2,weanti/Reaping2,abannerth/Reaping2