This change switches the debug symbol format from /Zi to /ZI for debug builds of blender, allowing Edit and Continue to work. This allows limited [1] code changes in the debugger without having to stop the process and recompile a new binary leading to improved developer productivity. All MSVC versions we support support this flag, Clang on windows does not mind the /ZI flag, but doesn't currently emit the required information to have this feature work. [1] https://docs.microsoft.com/en-us/visualstudio/debugger/supported-code-changes-cpp