Kokoro changes:
- Linux: gcc-13, cmake-3.31.2
- Windows: python 3.12, cmake-3.31.2
* Disable warnings in gtest, gmock
This is required in order to build with GCC 13, and Apple Clang with warnings-as-errors
Bug: crbug.com/383538610
* disable license check on .github/workflows/main.yml
* Use add_subdirectory for internal gtest, gmock
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Co-authored-by: Antonio Maiorano <amaiorano@google.com>
`license-checker` is a tool that verifies each file has contains a permitted license header.
See https://github.com/ben-clayton/license-checker for more information.
Also add missing licenses to presubmit scripts.
presubmit.sh now runs presubmit-docker.sh using the new radial
docker image which contains various toolchains.
The `/bin/using.sh` bash script exports the `using` bash function
which can be called to configure toolchains at specific versions.
