Detect CMake non-target directives

CMake directives can be target-specific - generally starting with target*() like target_compile_options() versus non-target-specific like add_compile_options() or include_directories(). It’s usually recommended to use target-specific directives whenever possible, as they provide better scope control over individual targets, avoiding applying directives in unexpected scopes.

CMake provides a warning flag -Wnon-target-directive to detect such directives. Sometimes they may be truly unavoidable or in a third-party library out of one’s scope.

cmake -Werror=non-target-directive -B build

or to only warn without treating it as an error:

cmake -Wnon-target-directive -B build