Add CMP0075 opt-in.

Fixes #1376

Author: SiegeLordEx

CMakeLists.txt

@@ -31,6 +31,9 @@ if(COMMAND cmake_policy)
     if(POLICY CMP0060)
         cmake_policy(SET CMP0060 NEW)
     endif()
+    if(POLICY CMP0075)
+        cmake_policy(SET CMP0075 NEW)
+    endif()
 endif(COMMAND cmake_policy)
 
 if(NOT CMAKE_BUILD_TYPE)