add separate option CATKIN_INSTALL_INTO_PREFIX_ROOT

[dirk-thomas]

The existing option CATKIN_BUILD_BINARY_PACKAGE is being used in the generated Debian rules files (except for catkin itself). Currently that flag has two effects:

• It disables tests:

  • catkin/cmake/test/tests.cmake

    Line 47 in cbe8368

    if(NOT CATKIN_BUILD_BINARY_PACKAGE)

• It skips the installation of files into the root of the install prefix:

  • catkin/cmake/all.cmake

    Line 197 in cbe8368

    if(CATKIN_BUILD_BINARY_PACKAGE)

  • catkin/cmake/catkin_generate_environment.cmake

    Line 77 in cbe8368

    if(NOT CATKIN_BUILD_BINARY_PACKAGE)

When building ROS 1 packages with colcon the second side effect is desired when building with --merge-install but the first one is not. In order to select that combination this patch introduces a new flag named CATKIN_INSTALL_INTO_PREFIX_ROOT. The value of this new variable is being initialized based on the value of the existing variable CATKIN_BUILD_BINARY_PACKAGE (in case it is not being passed explicitly from the command line). This allows colcon-ros to pass -DCATKIN_INSTALL_INTO_PREFIX_ROOT=0 while still keeping tests enabled (see colcon/colcon-ros#11).