I solved this by writing the following PowerShell script and running it in my profile startup script. Each time it is run it copies any settings that have been added to the user's .gitconfig to the global one and then replaces all the text in the .gitconfig file with and [include] header that imports the global file.
I have solved this problem using a slightly different approach that I have seen work for other configuration files. Git Config supports includes that allows you to point to a configuration file in another location. That alternate location is then imported and expanded in place as if it was part of .gitconfig file. So now I just have a single entry in .gitconfig:
I wanted to put .gitconfig and other bash files in E, so I created a folder called 家 where I want them all in. mkdir home
Go to 等等 folder and open the file called 侧写 (In my case, it's E:\git\etc\profile)
Add absolute path to the 家 directory we created (or to the directory where you want to have your .gitconfig file located) at the end of the 侧写 file. HOME="E:\git\home"