adjusted mode of some CMake messages (#8278)

this allows CMake to fail with `-Werror=` is specified

Author: firewave

cmake/options.cmake

@@ -25,7 +25,7 @@ option(ANALYZE_TYPE         "Build with TypeSanitizer to detect aliasing issues"
 option(WARNINGS_ARE_ERRORS  "Treat warnings as errors"                                      OFF)
 if(WARNINGS_ARE_ERRORS)
     if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.24")
-        message(WARNING "WARNINGS_ARE_ERRORS is deprecated - please use CMAKE_COMPILE_WARNING_AS_ERROR instead")
+        message(DEPRECATION "WARNINGS_ARE_ERRORS is deprecated - please use CMAKE_COMPILE_WARNING_AS_ERROR instead")
     endif()
     set(CMAKE_COMPILE_WARNING_AS_ERROR On)
 endif()
@@ -58,9 +58,9 @@ if(BUILD_CORE_DLL AND NOT MSVC)
 endif()
 # need to check before the option() specifying it or it will be defined
 if(DEFINED BUILD_TESTS)
-    message(WARNING "BUILD_TESTS has been deprecated and will be removed in Cppcheck 2.22 - please use BUILD_TESTING instead")
+    message(DEPRECATION "BUILD_TESTS has been deprecated and will be removed in Cppcheck 2.22 - please use BUILD_TESTING instead")
     if(DEFINED BUILD_TESTING)
-        message(WARNING "BUILD_TESTS and BUILD_TESTING have been defined at the same time - ignoring BUILD_TESTS")
+        message(AUTHOR_WARNING "BUILD_TESTS and BUILD_TESTING have been defined at the same time - ignoring BUILD_TESTS")
     else()
         set(BUILD_TESTING "${BUILD_TESTS}")
     endif()