[CMake] Install target and Component (once more)

[Nicolas Burrus]

Hi,

After some mailing list browsing, I could not find any complete answer
to a recurrent request: how can we specify at configure time the
component which should be installed by the install rule?

Right now, I'm using the following custom rule:
ADD_CUSTOM_TARGET(install-runtime COMMAND ${CMAKE_COMMAND}
-DCOMPONENT=Runtime -P cmake_install.cmake)

But it implies running "make install-runtime" instead of the standard
"make install" (it seems like a custom target cannot replace a
predefined rule like "install").

Is there already a trick to avoid this? If the answer is no, let me
transform it into a feature request :-)

CPack handles this properly, and I can't see any good reason (but I'm
not a cmake expert !) for Cmake not to automatically propagate the
CMAKE_INSTALL_COMPONENT variable into the cmake_install.cmake script,
like it already does for CMAKE_INSTALL_PREFIX.

This way, something like
SET(CMAKE_INSTALL_COMPONENT "Runtime") would do the job.

In particular, this feature would be really useful when a project
embbeds some library subprojects, whose header files should not be
installed when they are just used to build the main program.

Thanks,
Nicolas Burrus