Use makefile->IssueMessage() to print the unprocessed watch message in a
format consistent with other CMake messages and with a more complete
call stack for the access.
When a watch does not specify a command to call then variable_watch
prints out a message to stderr. Remove code after that which collects
all variable values to construct a message that is never printed.
Otherwise such code causes a READ_ACCESS watch to trigger on all
variables in the currents scope.
Reported-by: Yichao Yu <yyc1992@gmail.com>
This converts the CMake license to a pure 3-clause OSI-approved BSD
License. We drop the previous license clause requiring modified
versions to be plainly marked. We also update the CMake copyright to
cover the full development time range.