GitLab

* [clang-tidy] Do not use else after return

Found with readability-else-after-return
Signed-off-by: Rosen Penev <rosenp@gmail.com>

* [clang-tidy] Convert several loops to be range based

Found with modernize-loop-convert
Signed-off-by: Rosen Penev <rosenp@gmail.com>

* [clang-tidy] Replace deprecated C headers

Found with modernize-deprecated-headers
Signed-off-by: Rosen Penev <rosenp@gmail.com>

* [clang-tidy] Use auto where applicable

Found with modernize-use-auto
Signed-off-by: Rosen Penev <rosenp@gmail.com>

* .clang-tidy: Add these checks