cmake: We should start Issuing a warning when users use the undocumented -H<src_dir> functionality
Since the new functionality provided by -S
is a super-set of that provided by -H
( it supports -S<space><source_dir>
) we should start warning when -H
is used.
While MR #2358 removes the internal CMake usage of -H
it doesn't add a warning so that existing build trees will not start generating warnings when used with a new version of CMake. Instead we should wait a reasonable amount of release and than introduce the deprecated warning.