clang-tidy: performance-inefficient-string-concatenation
With cmStrCat
provided by !3628 (merged), we can enable clang-tidy's performance-inefficient-string-concatenation
check.
Here is a test build that flags some places that could benefit from this new function: https://open.cdash.org/viewBuildError.php?type=1&buildid=6037049
cc: @sebholt