build(lint): fix luacheck not found #18940

Problem:
Since 6d57bb89c1ee #18543, luacheck is not found on some systems when
running the "lintlua" target.

Solution:
- Move the find_program() to the top-level CMakeLists.txt
- Define a def_cmd_target() function with fewer assumptions than the old
  lint() function.
- Move "lintuncrustify" to src/nvim/CMakeLists.txt so it can reuse the
  $LINT_NVIM_SOURCES already defined there.
- Make the lint targets _fatal_ by default. There is little reason for
  the "lint" umbrella target defined in Makefile to exist if it's going
  to ignore the absence of the actual linters.
- For now, keep the uncrustify call in a separate cmake script so that
  it can be silenced (too noisy).

0 files changed, 0 insertions, 0 deletions