[CMake] Compile flags for a single file

[The Novice Coder]

 I've been trying most things I can think of, but have been unable to 
 come up with a solution.. the basic gist is I need to change the compile 
 flags for a SINGLE file within a project. Specifically, disabling all 
 compile warnings for that file.

 add_definitions() seems to effect the whole project, so that's not 
 helping..

 Also couldn't use set_property() to do it either. (I could have been 
 using it wrong).

 Thanks!


 Extra nonsense:
 If you're wondering why, it mostly has to do with politics.  An outside 
 vendor wrote that file and we are not allowed to modify it... and they 
 refuse to fix the warnings.  We're also required to treat warnings as 
 errors, so this comes as a stand-still and breaks automated build 
 machines, as after the projects are generated, they have to manually be 
 updated (right now.).