exec_program
------------

Deprecated.  Use the execute_process() command instead.

Run an executable program during the processing of the CMakeList.txt
file.

::

  exec_program(Executable [directory in which to run]
               [ARGS <arguments to executable>]
               [OUTPUT_VARIABLE <var>]
               [RETURN_VALUE <var>])

The executable is run in the optionally specified directory.  The
executable can include arguments if it is double quoted, but it is
better to use the optional ARGS argument to specify arguments to the
program.  This is because cmake will then be able to escape spaces in
the executable path.  An optional argument OUTPUT_VARIABLE specifies a
variable in which to store the output.  To capture the return value of
the execution, provide a RETURN_VALUE.  If OUTPUT_VARIABLE is
specified, then no output will go to the stdout/stderr of the console
running cmake.