When you want to exclude a file from compilation without deleting it, it is enough to change its extension, e.g. from ".c" to ".c_".

Alternatively, you could move such a file to a subdirectory "Attic" or the like.

Any of these solutions would ensure that globbing will no longer include that file in the list of source files, without needing to update any project configuration files.

And nothing that shouldn't happen ever does. I guess you also include "." in $PATH, even roots.