Compiling native applications (C, C++, etc.) is ridiculously parallel, having more cores is almost always better in that case. Having said that unless you are compiling large projects such as Linux kernel, Firefox or LLVM this shouldn't be a massive issue. Obviously for testing it will depend on what software as to whether you'll need the cores. Interpreted/JIT languages (Python, JS, java, C# which you may be using for game development) I believe single-core speeds may be more ideal.