KWIML: Avoid if() quoted auto-dereference

When testing CMAKE_<LANG>_COMPILER_ID values with if(STREQUAL), do not
explicitly dereference or quote the variable.  We want if() to
auto-dereference the variable and not its value.
Merge branch 'upstream-kwiml' into update-kwiml
Merge topic 'update-kwiml' into next

659605fb Merge branch 'upstream-kwiml' into update-kwiml
4871885b KWIML: Avoid if() quoted auto-dereference