When using `<LANG>_CLANG_TIDY` our internal launcher for the tool must
capture its return code and stderr and report them on failure.
Otherwise incorrect command lines silently fail.
Closes: #16435
Run the `Utilities/Scripts/clang-format.bash` script to update
all our C++ code to a new style defined by `.clang-format`.
Use `clang-format` version 3.8.
* If you reached this commit for a line in `git blame`, re-run the blame
operation starting at the parent of this commit to see older history
for the content.
* See the parent commit for instructions to rebase a change across this
style transition commit.
Create a <LANG>_CLANG_TIDY target property (initialized by a
CMAKE_<LANG>_CLANG_TIDY variable) to specify a clang-tidy command line
to be run along with the compiler.