Merge topic 'block-management'

44a2f3f332 Add new flow-control commands for variables and policies scopes management
604993248f cmMakefile::VariablePushPop: helper class to manage variable scopes
3d94ee0e03 cmMakefile::RaiseScope: Add support for cmValue argument
553da0685f cmFunctionBlocker: Add handling of close block without parameters.
02c067dee5 cm::enum_set: fix various bugs

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: John Ericson <git@johnericson.me>
Merge-request: !7575