GPG info trips up git log parsing

I've got some settings that add more information to `git-log`, which results in the log parsing scripts failing at cmake-time with the following error:

````
CMake Error at CMakeLists.txt:585 (math):
math cannot parse the expression: "gpg: Signature made Thu 04 Sep 2025
04:58:12 AM PDT

gpg: using RSA key B5690EEEBB952194

gpg: Can't check signature: No public key

1756987092

/ (60*60*24)": syntax error, unexpected exp_NUMBER, expecting end of file (36).

-- Version number: 11.90.ERROR
````