Gentoo uses cmake -C <...>/gentoo_common_config.cmake approach to set toolchain variables.
There is nothing wrong there, so there is no need to print huge ROCMChecks warnings.
--- a/share/rocmcmakebuildtools/cmake/ROCMChecks.cmake
+++ b/share/rocmcmakebuildtools/cmake/ROCMChecks.cmake
@@ -34,20 +34,6 @@ function(rocm_check_toolchain_var var access value list_file)
         elseif("${base}" MATCHES ".*/CMakeFiles/${CMAKE_VERSION}$")
             set(cmake_module On)
         endif()
-        if(NOT cmake_module)
-            message( "
-*******************************************************************************
-*------------------------------- ${message_title} --------------------------*
-  Options and properties should be set on a cmake target where possible. The
-  variable '${var}' may be set by the cmake toolchain, either by
-  calling 'cmake -D${var}=\"${value}\"'
-  or set in a toolchain file and added with
-  'cmake -DCMAKE_TOOLCHAIN_FILE=<toolchain-file>'. ROCMChecks now calling:")
-            message(${message_type} "'${var}' is set at ${CMAKE_CURRENT_LIST_DIR}/CMakeLists.txt:<line#> shown below:")
-            message( "*-----------------------------------------------------------------------------*
-*******************************************************************************
-")
-        endif()
     endif()
 endfunction()
 if(UNIX AND (ROCM_WARN_TOOLCHAIN_VAR OR ROCM_ERROR_TOOLCHAIN_VAR))