Changes necessary to resolve c26451 warnings in this file. https://docs.microsoft.com/en-us/visualstudio/code-quality/c26451?view=vs-2019

Exact warning messages:

D:\projects\blender\source\intern\clog\clog.c(307): warning C26451: Arithmetic overflow: Using operator '-' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator '-' to avoid overflow (io.2).
D:\projects\blender\source\intern\clog\clog.c(308): warning C26451: Arithmetic overflow: Using operator '-' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator '-' to avoid overflow (io.2).
D:\projects\blender\source\intern\clog\clog.c(569): warning C26451: Arithmetic overflow: Using operator '+' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator '+' to avoid overflow (io.2).