I updated the ale-c-clangd linter to match the ale-cpp-clangd linter and added a test case for automatic detection of compile commands. My last commit a1fab59 has a fix for certain variables leaking out of the test and causing mayhem. I'm sure this fix is not perfect, but I'm unfortunately a total noob when it comes to VimScript so I'm not immediately sure how to do it better.

EDIT: Two things I wanted to note:

1. It appears that a few of the c/cpp linters only have tests for c. Maybe we should add a new issue to add tests for cpp? Would mostly be copy & paste (since the linters themselves are practically identical), which may explain why they aren't duplicated.
2. Both the clang-tidy linter and the clangd linter allow the user to specify miscellaneous additional flags. If the user specifies the build directory AND the linter automatically detects a build directory, clangd/clang-tidy will fail to run, stating that the associated build dir flag can only be specified zero or one times. Should this be considered user error, or should we handle this condition somehow?
3. The ale_c_parse_compile_commands variable doesn't appear to do anything. Am I missing something, or is this a bug?

Cheers! 🍻